Mermaid Tethys is a hybrid control-healer whose value comes from flexibility rather than raw throughput. At max skill, Death Reef can either petrify a target that has not acted yet or deliver a strong heal if used on an ally that already moved, and the skill also adds extra sustain through lowest-HP healing, permanent reflect for the team, and temporary defensive buffs for Tethys herself. Her awakened passive makes the mechanic much smoother because Death Reef always leaves a dormant follow-up at the original position, which improves her consistency over longer fights.
She is still a niche pick in Pve and PvP because her control is conditional and her tempo is slower than top supports, but she can be useful in beginner or budget teams that want some healing without giving up all disruptive potential. Tethys also becomes more interesting in Poseidon-oriented lineups, since her passive gives him a direct boost and eventually grants him a max-level Death Reef package. Outside of that synergy, she is mostly a utility option, not really used in PvP or even PvE, just for collection.
