I’ve witnessed an interesting discussion at discord feedback channel about “Black Hole” functionality. It was about it’s full time CC and imbalance as a result. I totally agree with that and, since Judd (Mox) said the question deserves to be discussed by developers, I also perceived this as an opportunity to reveal my own ideas about the spell 
First of all I must say that I don’t think this spell should blindly copy known functionalities (like D3’s “Black Hole” or “Piranhado”). Also, current functionality or D3’s “Black Hole” makes this spell to be used in one way only - cast it and cast something more damaging over pulled crowd… or even cast this single spell in a loop if it’s damage is enough. And that’s why I suggest to make it less control and more damaging, saving an opportunity to advance it to something similar with current “Black Hole”.
And of course I’ll try to take into account information we already know about the future of this spell (like, revealed “double star” effect).
So …
Skill: Black Hole.
Categories: Spell, Cold
Description: creates a Black Hole in a target area. It severely slows enemies in a small area around and causes weaker slow effect in much larger area. After some time Black Hole collapses, pulling enemies to its center and damaging them in large area.
Visuals:
“Black Hole” appears in a target area. It’s a dark sphere but it has blue / violet outer glowing. That glow is not static and gives understanding that sphere is rotating. Same color vortex is slightly visible around the sphere. There’s also a larger vortex, but it’s slower and even less visible. Black Hole’s sphere and vortexes become brighter when the Black Hole is about to collapse. Vortexes twirl faster and faster and slowly shrink to the center. And then all this rapidly collapses within a few moments. A short flash appears in the end.
Functionality:
Cost: 50 mana.
Cooldown: 10 seconds.
Duration: 4 seconds.
Black Hole reduces movement speed and attack / cast speed of all affected enemies. This effect has an average area, but it’s much stronger in a smaller area around the sphere. Small radius = 40% of total radius.
Weaker slow, movement: 20%
Weaker slow, attack / cast: 10%
Stronger slow, movement: 40%
Stronger slow, attack / cast: 20%
Black Hole starts to collapse for 1.5 seconds before its end. It sounds slightly different at that moment (additionally to the visual effects), so the player could react to this event. And when it collapses all enemies in entire effect area are pulled to the collapse center and take significant amount of damage. Pulling distance is equal to 30% of maximum radius of effect.
Specialization nodes:
All below nodes scheme:
Greater mass: [5 levels]
Overall area of effect is increased by 10% per node level. Area of stronger effect is also increased.
Stronger pulls: [10 levels, requires Greater mass 1 or Gravity shock 1]
Pulling distance is increased by 10% per node level. Also every enemy may be pulled to newly created Black Hole with 10% chance per node level
Gravity shock: [5 levels, requires Stronger pulls 2 or Double Star 1]
When the Black Hole appears, all affected enemies gets 7% collapse damage per node level. They get additional 7% collapse damage if they were inside smaller area of effect or they were pulled inside it. Note: this damage is dealt AFTER enemies were pulled by the effect of “Stronger pulls” node. This bonus damage is notably higher than “Big Bang” bonus, but it shouldn’t be to high, as it’s instant.
Double Star: [1 level, requires Gravity shock 3 or Light Storm 3]
Black Hole is now a double star system. Sister star appears nearby and they both orbit system’s center. Radius of area of stronger effect is increased to 60% of overall effect radius. All enemies inside this area now gain halved benefit from any bonuses to movement, attack and cast speed. Sister star has bright blue color, nearly white. It’s smaller than the Black Hole, and it’s easily observable that this beautiful star is being constantly consumed by her dark sister. Both stars collapse together.
Light Storm: [3 levels, requires Double Star 1 or Bearing the stars 3]
All enemies inside the stronger effect area are blinded. When Black Hole collapses enemies remain blinded for 2 seconds per each node level after first. Effectiveness of this blind effect is increased by 33% per node level. Blindness reduces chance to perform critical hit by half. And this means that this node at max level reduces enemies’ critical chance to 0%.
Bearing the stars: [7 levels, requires Light Storm 3 or Supernova 1]
Enemies’ health regeneration and their gained healing is reduced by 15% per node level. Also they lose 1 mana every second per node level when they’re inside the area of stronger effect.
Supernova: [1 level, requires Bearing the stars 3 or Rip the Space 3]
When the Black Hole collapses it doesn’t pull enemies towards center anymore but knocks them back with the same power. Also Black Hole doesn’t deal damage with the collapse anymore but it explodes, covering 70% larger area, and deals 50% of collapse damage per second for next 3 seconds (so it’s 150% over 3 seconds). This damage is always dealt as Fire. Note, that cold damage of “Gravity shock” node remains unmodified by this node, though spell gains “Fire” category from now on. Animation of collapse became brighter and it starts sooner. Explosion has its own colossal effect / animation and its consequences remains in the area for 3 seconds.
Hug of the Void: [5 levels]
Movement speed reduction is increased by 4% per node level and attack / cast speed reduction is increased by 3% per node level. So at max weak effect reduces m-speed by 40% and a/c-speed by 25%, while strong effect reduces m-speed by 60% and a/c-speed by 35%.
Compressed gravity: [4 levels, requires Hug of the Void 1]
Black Hole continues to slow enemies (weaker effect) even after it collapses. This effect remains in the area for 1.5 second per node level. Note: it’s still an area effect, so enemies can leave the area to prevent its influence on them.
Gravity surfing: [1 level, requires Compressed gravity 2]
While inside the area of Black Hole effect the caster gains bonus to his movement, attack and cast speed with the same effectiveness as his enemies are slowed down with. Note: So if he’s inside smaller area he gains greater bonus. Also this effect should be visually observable - like blue / violet haze and rays which are greater near caster’s feet and always directed to the Black Hole.
Ride the Wave: [4 levels, requires Gravity Surfing 1]
After the Black Hole collapses with its caster inside the area of effect, the caster remains hastened by weaker speed up effect for 1.5 second per node level, wherever he moves after that. Note: Unlike “Compressed gravity” functionality, this node’s effect isn’t area bound and the caster may move freely after this buff is gained. But the caster still needs to be inside the collapse area, when it happens, to get this buff. Also this buff is always a weaker version, wherever the caster is located at the moment of collapse.
Hyper-Kinetics: [5 levels, requires Gravity Surfing 1]
Any projectiles move 20% faster and further per node level inside the Black Hole’s area of effect. Also caster’s damaging projectiles deal 15% increased damage per node level to any target inside the area of effect. Note: this effect can’t be prolonged by “Ride the Wave” node.
Star Guide: [1 level, requires Ride the Wave 3 or Hyper-Kinetics 3]
Caster’s allies also gain bonus from “Gravity Surfing”, “Ride the Wave” and “Hyper-Kinetics” nodes.
Entropy: [5 levels]
Enemies inside stronger effect area suffer from reducing their armor and all protections by 20 per node level.
Big Bang: [10 levels, requires Entropy 1 or Catalyst 1]
Collapse damage is increased by 10% per node level. Note: this node increases overall collapse damage, while any other node may deal PART of collapse damage. And this means that this node increases effectiveness of any other damaging node of this tree. Even “Supernova” damage is dealt as a part of collapse damage.
Accretion disk: [1 level, requires Big Bang 3]
Whole area of stronger effect becomes an Accretion disk igniting enemies every second. For every enemy killed inside the Accretion disk collapse damage increases by 10% up to a maximum of 50%. All damage done by the Black Hole and by any of its effects is dealt as Fire. Black Hole’s glow becomes fiery and colors of vortexes also become more fitting these changes. Lesser vortex transforms into Accretion disk with its own animations and effects which are also much more noticeable. Note: This spell loses it’s “Cold” category but gains “Fire”. This node doesn’t change Supernova animation, as it initially has fire concept. But sister star of “Double star” node is definitely changed to the fire one.
Fuel for Apocalypse: [3 levels, requires Accretion disk 1]
Bonus per enemy death of “Accretion disk” node increases by 5% per node level. Maximum bonus also increases by 25% per node level.
Hell flame: [5 levels, requires Fuel for Apocalypse 2]
Accretion disk now deals 4% of collapse damage per node level every second. And since this damage is a collapse damage, it can be increased by “Big Bang” and “Fuel for Apocalypse” nodes.
World Arsonist: [1 level, requires Hell flame 2]
Duration of Black Hole and duration of Supernova collapse effect are increased by 1 second. Also cooldown of Black Hole is reduced by 2 seconds. Note: increased duration of Black Hole means that Black Hole collapses later. So it is harmful for instant effects but useful for continuous effects.
Catalyst: [5 levels, requires Big Bang 2 or ]
Reduces Black Hole’s cost by 5 mana per node level. Also reduces cost of all Cold skills by 1 per node level, while caster is inside area of effect. This reduction is doubled while the caster is inside the area of stronger effect. With “Accretion disk” node this node’s bonus is applied to Fire skills instead of Cold.
Point of Nullifying: [3 levels, requires Catalyst 3 or Rip the Space 3]
Black Hole is surrounded with small but extremely damaging area. Radius of this area equals 15% of total radius. This radius is unaffected by any radius changing effects (like Grater mass). All enemies in this area get damage every second in amount of 5% collapse damage per node level. Also in this area the damage of collapsing Black Hole is increased by 15% per node level. Last bonus if also applied to Supernova effect in this area.
Unstable sector: [1 level, requires Point of Nullifying 3]
Upon creation of Black Hole 3 more smaller black holes are created randomly in the area of effect of main Black Hole. Those holes can’t slow or pull, can’t have Accretion disks etc. but they are additional Points of Nullifying. These holes look completely like main Black Hole but they’re much smaller. Holes randomly appear on the radius lines which are sides of 8 equal angles (area circle is equally divided by 4 lines) - each on its own radius line. They also randomly located on the chosen line - it’s a point between 30% and 80% of radius.
Rip the Space: [3 levels, requires Point of Nullifying 3 or Supernova 1]
Cooldown is reduced by 1 sec per node level and duration is reduced by 0.3 sec per node level.
Grabbing all: [5 levels, requires Stronger pulls 4]
Upon creation Black Hole pulls enemies from OUTSIDE of initial area of effect with 100% chance. Outer radius of this effect equals 5% of overall radius + 5% per node level. So it’s 30% at max.
Realm trap: [1 level, requires Grabbing all 3]
A barrier appears on the border of Black Hole’s area. And from now no enemy can leave the area in any way, until Black Hole collapses. Caster and his allies can cross the barrier freely. Also enemies still are able to perform ranged attacks and spells through the barrier.
Legendary item example:
Item type: staff (I hope they’ll be implemented)
Item name: Void’s Gatekeeper
Description:
Any enemy close enough to the Black Hole is consumed by it, and returns only just before the collapse, getting 50% additional collapse damage. If his remaining health is less then 20%, he dies.
Visuals:
Staff is made of dark brown wood with several rough, black and pretty wide iron rings, which are located along entire staff length. It is crooked and starts twisting at some point. This twisting gets stronger to the top, which ends with the sphere of absolute blackness. Though it’s not static, not dead, and it’s outlines are slightly shudder.
When this staff is used with any skill except the “Black Hole” - it doesn’t change. And otherwise, dark red burst appears around sphere of blackness, while the sphere itself remains absolutely black.
Created Black Hole gains a sister star which is very dark, even darker than the main star, with slightly seen dark red glow. So the Black Hole is now a double star system. And if it has a “Double star” node, than it becomes a triple star system. Dark red star is the smallest of three.
Functionality:
- Radius of consume area equals to 15% of overall area radius.
- Collapse damage, which is dealt after enemies returning, is instant, and it can’t be changed by any nodes like “Supernova”.
- Consumed enemies can’t perform any actions, can’t regenerate health, mana, skills etc. Buffs and de-buffs are also “frozen” and their timers continue only after enemies return.
Bonus suggestion :
How about making staves as weapons which greatly increase spell damage (more than scepters and wands), but also increase their mana cost?
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