The manatear has many dangers that can befall a traveler, but it frequently described on a basis magnitude. Multiple metrics are used to describe these situations.

Aggression - How much an entity or group seeks others to add others to their number.
Strength - The ability of an entity or group to actually act on their aggression or those who provoke them.
Conversion - How quick an entity or group can change an otherwise unwilling target.
Overwrite - How much a personality or behavior is modified.
Duration - How long a specific shape is enforced if all else is left unchanged.

Kobolds tend to be mediocre on the first three metrics, occasionally catching a traveler through concentrated team effort. They'll typically take a good while to transform someone unless they have handy tools like the mask in the art piece. The last two metrics however are on upper end. Spellfluxed turned into kobolds have much of their behavior changed though it lightens up a tiny bit once the new member of the warren is integrated, and the shape is considered lasting as long as the spellfluxed is submersed in the kobold culture. Should the kobold warren have a dragon all of these metrics are intensified as the dragon literally needs the kobold fanclub/cult in order to stay physically healthy in the manatear.

Kobolds in the mana tear have some wide variety partially based on what the original form of the victim was, settling into broad categories that multiple common forms would fall into. For example Weasels(Dooks), and snakes would likely become small river dragon styled kobolds with aquatic toned scales. It's also that it lets noodles stay noodles and I require that as an artist. this means dragon kobolds, rat kobolds, dog kobolds, and the such all exist in these warrens.(they are just not designed more specifically yet, but they are all smaller than the average spellfluxed.)

Kobolds are very aware of the situation around their warren, should they realize they have someone that the outside world would much prefer to have not stuck in a minisociety in the middle of no where, diplomats and such, instead of transforming them they'll kick them back outside the front door. Unless of course you are a nobody at which point you can be a nobody in the warren.

Hans was held and captured for a good long while in the dark before the kobolds came bearing the mask to force on him. The change happened quickly and left him very confused, but as soon as a pickaxe was placed into his hands there wasn't any question about what his job was.