What are best Cocytus teams and builds?

He's awesome and id like to run him successfully. Yeah i know he doesn't show up on top 10 pvp and that not every level needs the same few units, but i want a pretty legit arena team and to be able to run him in expeditions and giants/dragons/confusion etc

Best relics? (Game says vertmere or desolation. Anybody have differing arguments?)

Best arc light?

Up to 40% more damage on his unique arc can be great, but it's slow to build in most content. [Justice has arrived] is a powerful healing arclight to keep him up longer. Or [perception] for big dmg reduction, but cocytus is slow and will be the last to take action most of the time and already live/die from ult attacks before brain finishes him off. But I'm here for insight.

And what teams would you say he fits in well? (And whose leader skill)

Armor bedo, lupisregina and a dps work fair but I'm open to ideas. The dps ranging from mage albedo or demi or momon. Once in a yuri as the 1 tank, and some pve content with no heals. Cocytus sweeps in every sence of the word lol(and all the more after demi and/or albedo add more dots on top of his passive and optional leader skill)

If there are spreadsheets for this all the better.(saying team comps and how to build units etc)