Are there any vegetarian or vegan-friendly izakaya around Tokyo?

I have been put in charge of planning a friend’s birthday activities (mainly, going to an izakaya and then to roppongi for clubbing). However, she’s a very strict vegetarian and I don’t want her to be limited to only eating edamame on her birthday. Does anyone know of an izakaya that serves a wider variety of vegetarian or vegan food, can accommodate a large group of people, and isn’t too expensive (we’re students, after all)? We live in Saitama, so anything in the area is fair game, but we don’t want to go too far out of our way.

Thanks!