Frog Zelos is designed to punish faster teams by spreading Mucus and disrupting turn order. He is not a meta PvP pick in the current environment, but he can still be useful for new accounts that need a simple speed-control option without heavy investment.
At max skill levels, his game plan is straightforward. Skill 2 is his core action, with high Mucus application chance and extra spread to adjacent turn-order targets. Skill 3 adds team-wide pressure if enemies are faster than your side, and can reduce targets to 1 initial Speed for 2 turns once they reach 3 stacks after acting. Skill 4 gives him a large bonus to Status Inflict Chance against faster enemies, improving consistency in the matchups where he is expected to perform.
Zelos is a niche anti-speed controller for beginner and collection-focused rosters. He can create tempo swings in early progression, but his value drops in competitive PvP where stronger and more reliable control units usually replace him.