T.E.N.G.U.

The T.E.N.G.U. ( T ranformer of  E nergized  N egativity  G usts of the  U niverse) is a M.O.A.B.-class bloon with 15,000 HP. It look like an orange/yellow MOAB. It is immune to wind/thunder-based attacks and moves as fast as a BFB. It has these abilities:
 * Eternal Tornado: Just like the apprentice's whirlwind, except this goes on until it leaves the screen and deals 2 HP damage on the way.
 * Sonic Missiles: 3 bright lights appear randomly in the screen, a second later, they shoot 5 tiny green bullets in a barrage form towards random towers. Each bullet deals 2 HP damage.
 * Tengu's Gust: Damages every tower on the screen by 2 HP damage and heals every bloon by 500 HP.
 * Tengu's Sonic Missiles: 5 bright lights appear randomly in the screen, a second later, they shoot 7 tiny green bullets in a barrage form towards random towers. Each bullet deals 4 HP damage. Replaces Sonic Missiles after it was used 2 times.
 * Dual Tornado: Shoots 2 tornadoes, just like the apprentice's tempest tornado, except this goes on until it leaves the screen and deals 4 HP damage on the way. Replaces Eternal Tornado after it is used 4 times.

Trivia

 * Obvious reference to Aya Shameimaru.
 * The BGM for its boss fight is The Youkai Mountain ~ Mysterious Mountain.