This is not true. All Runeblade skills except for Drain Evocation are Slash attacks that benefit from Slash Up, and do not benefit from Magic Attack Up. Drain Evocation is Magic attack and will be the only skill that benefits from Trousseau's party bonus.
Trosseau and Blossom in the Dark stacks.
it's Magic Atk Up and Man Eater on Magic Atk.
so Drain Evocation will get boosted by both cards, while Hazard Spell doesn't get boosted by any of them.
ODSTxGundam
Man eater upon magic attack. Does that mean my units apply the man eater bonus when they attack with mag atk or they get man eater when attacked with mag atk damage?
The VC give man eater but only for magic type attack. It is basically Salire TMR with global effect.
I believe there are no such VC that give you
such reaction ability as of now.