It's a sad day in Tennoverse when you have to press two buttons to become a discount [Nova]. Sure, Gloom's cap is 95% and you can get more than double damage with Reap, but then again Nova is much more versatile and if need be you can rely on a 200k damage nuke in Anti-Matter Drop.

However, it is not all gloom and doom with this frame as you can, after charging a meter for a good minute, be able to switch to his Shadow and do some real damage. You also get to do stuff when you're dead, but that's about it.

His other stuff:

Sevagoth's Shadow - https://overframe.gg/build/167025/

Sevagoth's Shadow's Claw - https://overframe.gg/build/167026/

Other notes and build justification:

High STR - if your Gloom isn't slow enough, you get hit. A lot.

Triple Umbral - When your enemies look gloomy and slow, they won't shoot you. This is literally "to survive longer, don't get shot" school of survivability.

Alternately, play Nova: https://overframe.gg/build/39855/