A troll can gain experience by killing animals or other trolls. Accumulated experience allows the troll to level up and gain new abilities or even change classes, as such, many players aim to increase their level before attacking, or attacking before their enemies can increase in level. There is a mode called -no exp which disables experience gain, trapping all players on level 1, forced to use only their basic skills in the game.
Players should note that if their targets are killed by allied towers or traps, there will be no experience from the killed unit. Thus, it is important to land the killing blow on an enemy unit with a troll, so good timing wll be required in the presence of traps and towers. This scenario most frequently appears in the case of hawks being pulled down from the air by Ensnare Traps.
With a Gem of Knowledge, the experience gained will be according to the following formulae:
- 50 x level of killed enemy normal unit
- 150 x level of killed enemy hero
- Experience Gain for killing any unit is 400%.
- Gem of Knowledge only gives bonus experience if you deal the killing attack/spell, and does not get the 400% bonus experience gain.
- In order to calculate the experience gained per Unit level, it uses a recursive formula. For a level 1 creep, it gives 25 experience. Experience for a level X creep would be F(x) = 1 * F(x-1) + 5 * x + 5 , which is then multiplies by the 400% experience gain.