Millipedes are docile and harmless to humans. Although some species are not considered social - that doesn't mean they cannot be housed with multiples of the same species. It simply means there is no known benefit of housing them in colonies. The social species benefit with more of either themselves or other species of similar living requirements as they groom and even form bonds with each other. Most are completely fine at room temperature with some harder species needing more warmth.

We keep a few species. Generally speaking, most species are ok in a regular household room (In the UK, this is about 20C and between 30- 60% humidity, depending on the season), but nearly all of them thrive more in a warmer, more humid environment. The majority of millipede species like to burrow and so you'll need a tub that has 3 times the length of you millipede of dirt. If you're keeping a giant train, this could be tricky. For arborial species, more space above the soil, but a lot of arborial species also come down for part of the day. It may all sound a little tricky, but it's not really. Millipedes are fun.

We don't have specific settings for things like humidity and ventilation because these are generally difficult to maintain, and generally speaking, a gradient in the tub you keep your isopods in will sort itself out. If you want to keep the more advanced species, then we should probably chat.

For comparison, "High" ventilation means we keep 3-5 air vents at the dry end of the enclosure (depending on the enclosure size), with that side pointing into the room and good air movement.