He is recruitable during "Superhero Robin" at Yamas PUB.
Wil is surely disappointing, at the time he is recruitable, he is a great battlemage, with 18 Strength and 19 Magic, but as time passes, Lisa, Neidhart, Ruby, Rich, etc. become better than him.
His physical capabilities are crippled when he equips the Night Medallion, he becomes old, but his Magic capabilty gets better, gaining 6 points in his magic.
His second cosplay item is obtained at the very end of the hack, the Kris Askarabes(?), obtained after defeating The Egg. Even though I cannot describe the boosts, you shouldn't be using him at this part of the hack.
Wil is a dedicated battlemage, or a real mage if you equip the Night Medallion, but lots and lots of character will get ahead of him.