Regeneration; Tough Hide
At the start of its turn, restores 2 HP if it has taken no magical damage since the end of its previous turn. Tough Hide reduces the first physical damage it takes each round by 2 (minimum 0).
Fantasy humanoid Challenge 4
A troll seeks damp forests, swamps, rocky fissures and abandoned underground spaces. In Elaria, stories about its origins involve wild magic and ancient transformations of the landscape. It may change its territory according to available food, but returns to a safe den. Remains of prey, broken branches and enormous tracks warn that something roams nearby that ordinary animals prefer to avoid.
It often lives alone, although trolls sometimes gather or answer to a stronger leader. It can remember successful hunting grounds, recognize recurring threats and try simple ways to obtain food. Hunger, defending a shelter or payment for service may motivate it. Not every troll is willing to talk, and not every offer will stop it, but a story can give an individual a comprehensible reason for blocking the road.
Regeneration restores two Health at the start of its turn if it has taken no magical damage since the end of its previous turn. Tough Hide also reduces the first physical damage each round. It is therefore important to maintain pressure and use the actual weakness in the rules: magical damage interrupts its recovery, and it need not be fire. The party can go around the troll, draw it away from the place it protects or discover who supplies it. A reputation for invincibility often develops because previous opponents did not understand its regeneration.

At the start of its turn, restores 2 HP if it has taken no magical damage since the end of its previous turn. Tough Hide reduces the first physical damage it takes each round by 2 (minimum 0).
At the start of its turn, restores 2 HP if it has taken no magical damage since the end of its previous turn. Tough Hide reduces the first physical damage it takes each round by 2 (minimum 0).
Physical + regeneration