Sea Dragon Kanon is one of the few characters that uses “Hard Control.” This type of hard control cannot be purified, although there are units that can avoid it. Its control consists of exiling a character to another dimension where they receive damage caused to their companions, and when they return, all that damage explodes (if it exceeds a certain amount). It sounds good, except that it costs 4 energy points. Too much for the current meta. It was used in the early days of the game, but today there are better units with equally interesting mechanics.
With Gold Triangle Dimension maxed, Kanon exiles an enemy for 1 turn and absorbs 80% of the Cosmo damage received by his teammates, dealing all that damage when the target returns. If the damage is enough to kill it, the overflow becomes 90% true damage to all enemies. Punch of Hatred adds 50% of the team’s P.DMG as True Damage if the target survives, or 50% of Kanon’s Max HP as True Damage if the exiled target’s teammates took no damage during the exile. On death, his brother Saga’s spirit inherits all his stats with 16% HP and continues the battle for 2 turns.
Unfortunately, there aren’t many characters with “Strong Control.” 4 energy points is too much for any meta; the damage isn’t enough, and its other mechanics don’t add anything. It’s a unit that might work in a very specific combo, but other than that, skip it.