Blade Maelstrom is PrimaryMonkeycard in Bloons Card Storm. It is a defender that gains +10 ATK during the opponent's turn. Additionally, at the end of the player's turn, it deals 30 damage to all Bloons on the opponent's side, regardless of its current ATK, even if it is stunned. Its On Turn End effect always occurs after Mortars and Necromancer.
The card art depicts a Blade Maelstrom firing a swarm of blades at Bloons on the Tree Stump map from Bloons TD 6.
Blade Maelstrom is effective against swarms of low-HP bloons, attributed to its On Turn End effect, similarly to a guaranteed Spike Storm!. The main attack is subpar but is a serviceable Defender against single bloons.
It's often better to keep its main attack ready as a Defender, rather than attack bloons.
Being stunned will not prevent its passive, so Stun Gas Bloons are not very useful against it.
Blade Maelstrom is most effective against Aggro, especially Swarm Aggro with Spooky Bloon as it can pop most 0 or 1 cost bloons before they leak.
Blade Maelstrom’s end of turn ability allows it to deal solid damage per turn even against larger Bloons, with every Bloon on the enemy’s side adding a flat +30 DPT.
The end of round ability makes it destroy the Bloons summoned from Red Bloon Apopalypse making it incompatible with RBA control decks as it goes against the role of stalling and preventing storm spawns. More specifically, Maelstrom ruins the stall at the second turn after playing RBA.