Small in stature but great in numbers, Gremlins use their countless military to their advantage in combat;

As they pierce you with their spears and arrows, a few of the Gremlins manage to wrap a thin, nearly invisible cord around your ankles. You trip, landing face first in the ashes. Then they bind your wrists and wrap the cord around your shoulders and legs. - Tome of Encounters (RPA-SQ1)

Gremlins can create a magical cord that is strong enough to restrain foes much larger than them and dissipates after a sizable amount of time;

As they pierce you with their spears and arrows, a few of the Gremlins manage to wrap a thin, nearly invisible cord around your ankles. You trip, landing face first in the ashes. Then they bind your wrists and wrap the cord around your shoulders and legs. Subdued, your captors declare victory. Long after they have abandoned the arena, your cords dissolve. - Tome of Encounters (RPA-SQ1)

At the Colosseum of Ashes, you fight a drove of Gremlins in the arena;

Looking more carefully at the ash in front of you, you see an army of Gremlins charging toward you, each no more than three inches in height. - Tome of Encounters (RPA-SQ1)

• You crush them all, using their size as an advantage.
• You are overwhelmed, with the Gremlins using their numbers to their advantage.

Making it to the Champion's Quarters of the Colosseum of Ashes, you find an army of Gremlins have established themselves therein;

You spot movement from the corner of your eye, but when you turn around there is nothing there. Suddenly, you feel a blade the size of a needle pierce the bottom of your leg. You look down to discover a Gremlin warrior pushing his sword into your flesh. Three rats dart toward you from across the room with Gremlin warriors mounted on their backs. Others descend from the ceiling with thin ropes and land on your shoulders.

“We claim this room,” one of them shouts in your ear, “in the name of the Shau’leeth Empire!” - Deathmatch at the Colosseum of Ashes (RPA-SQ1)