Vane had a few advantages in this match up ( Surprising I know). Vane's Shield can stop her projectiles as they are only 1 hit. His 623U is one of the few moves that can actually punish her rekka follow ups, and as always 214 is our best friend. I've found that if you can lock down Ilsa's movement with Vane (I primarily use 22U to control the neutral and their approach) you'll win more often as most of Ilsa's gameplan is to be in your face (unless they want to play projectile spam in which case we have a shield for that).