With Patch 0.9 just released and an influx of new players I thought it might be helpful for some guidance on one of the hardest early bosses in this game.
I already know from previous patches and influxes of new players, that this is a boss, that a lot of people struggle with.
In this video I am showing and explaining how to defeat Rahyeh, The Black Sun. The Timeline Boss from The Black Sun Timeline.
i agree. the first time i did rahyeh i had a terrible time.
got beat 14 times in a row.
crafted t5 movespeed on boots.
beat it on the next try.
Watched to make sure you recommended movespeed.
you did 
Nicely done video.
Ironically, I am stuck on Rahyeh, but that’s because his stupid DoT line move keeps glitching out and not showing, so I just die to a bug lol x) I was like OOOOH SOMEONE FIXED THE BUG? x(
That sounds awful, I am sorry to hear that.
I only had his wave dash making him dash offscreen once (you can actually see that in the video).
All my other attempts didn’t had any bugs or unintended behavior.
Did you try verifying game files?
very hard the first time !!!
and so easy when you stay out of the circle arena …
stay at the limit let him come , fight let him return in arena doing his things, return to the limit, wait him to come and so on … and take your time with that tactic
oops EHG will patch it lol
It’s okay, I think I managed to figure out how to do it – Just pop a potion before and pray lmao.
In all seriousness, I tried to wait until he drew the line before dashing, because that might have been part of the problem. I beat him on my third try thankfully 
I will verify the files tomorrow, hopefully!
Finally got Rahyeh down. Yay!