Clicker Heroes mercenaries are available to find more hero souls, rubies, gold, relics and even skils activations. The time for each task varies from 5 minus to 48 hours.
The short tsks are faster for reaching achievements for the various items. Longer times tend to be more risky as it seems that the game kills the mercenaries at a rate of 1/3 over 48 hours. The remaining mercemaries can create a new one for 8 hours completion time.
Mercenaries have various classes and specializations. Thase can be ignored as they are almost impossible to get the right tasks at the right time. The hero souls is probably the best choice as this allows the game to level up faster than gold etc. Skills and Relics are worthless diversions..
Occasionally a mercenary may die so its possible to create a new mercenary in 8 hours. Rarely the creation of a new mercenary results in the death of generating one.