Third, it will be a long time until he realizes he's reincarnated in the TWD universe, so please bear with me. I don't know if it will be Harem or not, ill figure it out later.
With water and ice he can diversify his attacks, from a shower of water droplets that are like needles to icy and destructive blasts, as well as shields and walls of ice that would take a lot of effort to break, this is clear only to his peers, cultivators not much stronger than he.