Squall, SeeD Mercenary

Two triggers pull against each other, and the friction between them is where the deckbuilding lives. Rough Divide keys off any creature you control attacking by itself, handing double strike to whichever solitary threat you commit: this 3/4 most of the time, but just as readily a lone evasive hitter you want to slip through unblocked. The second trigger is narrower than it reads. It fires only when Squall himself connects with an opponent, at which point you return a permanent of mana value three or less from your graveyard to the battlefield. That clause is not creature-locked: a mana rock, a cheap enchantment, a low-cost planeswalker, anything at three or under climbs back the instant Squall lands a blow. The two interlock most sharply on a solo swing that goes unblocked. Double strike means Squall deals damage in both the first-strike step and the normal step, so the recursion fires twice, pulling back two permanents from a single connection. The catch is that none of this is guaranteed: Squall has no trample, so a chump block eats the whole attack and returns nothing, double strike or not. Swing wide instead and you trade away Rough Divide entirely, since it only rewards the loner, but the recursion still triggers as long as Squall gets through. The distinction between "a creature attacks alone" and "Squall connects" is the whole puzzle: they are different clauses, and reading them as one breaks your own math.