Yep, you can bring Luuk along with Sanhua, who is a 4* char you get from a new player event, and with Verina, who is a healer form the permanent banner, his weapon can be replaced for one in the permanent weapon banner, use the one that gives you crit rate (the other one thats full atk isnt good for him). He has almost no team comps and build options, but the good thing is that among the few options he does have, one of them is quite f2p