Jacob Boss - Vile

Vile has the same attacks here as he has for most of the game, with an added Super / Desperation attack. That and you can actually see his life meter.

As with all Vile encounters, he is weak against Ice, but use of Zero's D-Glaive or X's improved half charges are faster (until the last hit).

Desperation Attack

Vile produces 6 equally spaced lightning bolts. They rotate around the screen for several seconds. Occasionally one of the bolts fade out, giving you a space to dash through unharmed. After they stop, they rotate the other way the same amount of time. This isn't particularly hard to dodge, but you cannot hurt Vile during it.

This can also be avoided by flying over the top of the screen with Zero. Release the fly to fall down around the time the rotation switches direction, since it will take about as much time to come down as it does to go up, and you don't want to lose time waiting on Zero to fall.

X's invincibility dash also dodges the lightning, if you happen to have them.