In the game of Island Troll Tribes, energy is one of the three survival stats which a troll requires in order to stay alive. It slowly decreases over time, and upon reaching 0, the troll will die. In order to replenish energy, players must use their sleep outside ability (dangerous as it reduces other stats by 20), or the sleep ability of either a Tent, Troll Hut or Mud Hut. As a precaution to energy loss, some players bring mana potions, which is also a useful safeguard against the infamous Hypnotist class.
Beginners tend to die frequently from energy loss as it is harder to notice than health. Some players, when venturing far from their main base, tend to bring a tent kit with them, or use materials on other islands to quickly make a tent, in order to prevent death by energy loss. However, the abundance of food when moving nomadically often does away with the need for a resting place, and usually only the 'sleep outside' ability and a Fire is needed under such circumstances.