Not sure exactly what that is but repotting should get rid of them. Remove the old soil, replace with new. If that is not preferable, soak the whole pot in a bucket of water so that all of the soil is under water. Any bugs in the soil will leave or suffocate. If your plant is inside and you take it outside to do this, keep it in the shade so the leaves don't burn.

Note that fig (Ficus) plants have latex sap inside them that can cause a rash like poison ivy on some people. If you damage the leaves or roots while handling the plant, avoid getting the sap on your skin. If you do get some on you, washing it off right away should help avoid getting a rash.

Centipede - confirm by counting the number of pairs of legs on each body segment. A millipede has 2 pairs/segment and a centipede has only 1 pair/segment, a single leg on each side of each segment. Centipedes are beneficial in that they feed on smaller insects, and their bite is poisonous but normally cause only a moderate reaction (think bee sting) unless an allergy to the toxin exists.

If you set the dry pot in a bowl away from children and sprinkle food grade diatomaceous earth (DE) in the bowl, the powdered DE will adhere to the exoskeleton (outer skin) of terrestrial arthropod's (arthropods are relatives of lobsters/shrimp/crayfish) and absorb cuticular waxes, cause them to rapidly lose moisture and die from desiccation. Alternately, you could prepare a soil drench using 1-2 tsp/ qt or liter of 1.47% imidacloprid. Image

Insecticidal granules (Marathon, Admire, Merit, Advantage, Gaucho) containing imidacloprid will work too, but if your soil is water retentive it can and probably will cause issues related to root health where the liquid drench will not.

Al

I would identify that as a millipede; I see 4 legs per segment and that rounded little body. Centipede legs and antennae are longer, as well. They are scavengers and attracted to moist locations with plentiful supply of wood, bark, plant debris and the like. They can be a common presence in potting medium.

Millipedes can be found in bags of potting medium from the store, if there is the tiniest hole. That's how many people find them in their containers at home.

Diatomaceous earth is pretty effective for their control, sprinkled liberally on the surface of the potting soil and/or in the saucer that the pot is sitting in. DE does not dissolve in water so no worries about that. Please don't resort to an insecticide for this issue.

Millipedes are not venomous, they don't bite nor sting.