4 star Halloween Kimimaro isn't unusual especially since he has been in pretty much every spending event since he came out and he is in the 100k special rebate (may be level restricted event). They very well could've spent 100k ingots, but if they're only 31k bp. If they don't have Susano Shisui then odds are they haven't spent 100k. There is nothing su*ious about that account and it's a server based game that is almost impossible to cheat in. If I had to guess on how they got 4 star Kimimaro probably would be they spent 40k+ on rng events he was in/recharge wheel (currently 80 frags in shinobi feast recharge) and got him with rng and redeemed the 40k 100 frags from Tsukuyomi rebate.