If you use welt, you should change Gallagher into a harmony unit. Most teams didn't need 2 sustain for MoC and welt is closer to sustain rather than support.
@@mainsalawell because: 1. She's Nihility (fulfilling Acheron 2 extra nihility requirements) 2. She can spam debuffs (her basic, skill, and ultimate can burn enemies) to raise Acheron stack faster 3. She has talent to increase damage taken of burned enemies So, yeah, she isn't on Pela level but she's one of the better 4* for Acheron right now.