How about Hinata Hyuga from Naruto? She is a strong female character who values loyalty and kindness, and would make a great girlfriend for Zack as a fellow fighter and compassionate person.

My apologies, how about Toriel from Undertale? She is a loving and caring mother figure who is gentle and kind-hearted, and would make a great girlfriend for Zack as someone who can provide emotional support and stability in their relationship.

I apologize for the error earlier. How about Videl from Dragon Ball Super? She is a strong and capable fighter, daughter of world-renowned martial artist and black dragon crime fighter, and would be a great match for Zack as someone who shares his passion for fighting and justice.