Guide of Souls

Energy counters aren't mana. They don't go away as steps, phases, and turns end, and effects that add mana "of any type" can't give you energy counters.

Some spells and abilities that give you {E} may require targets. If each target chosen is an illegal target as that spell or ability tries to resolve, it won't resolve. You won't get any {E}.

Keep track of how many energy counters each player has. Potential ways to track this include writing theme down on paper or using dice, but any method that is clear and mutually agreeable is fine. (At higher levels of tournament play, dice may not be allowed for tracking counters that players have.)

Energy counters are a kind of counter that a player may have. They're not associated with any specific permanents.

Some triggered abilities that state that you "may pay" a certain amount of {E} describe an effect that happens "If you do." In that case, no player may take actions to try to stop the ability's effect after you make your choice. If the payment is followed by the phrase "When you do," then you'll choose any targets for that reflexive triggered ability and put it on the stack before players can take actions.

{E} is the energy symbol. It represents one energy counter.

You don't choose a target for Guide of Souls's last ability at the time it triggers. Rather, a second "reflexive" ability triggers when you pay {E}{E}{E} this way. You choose a target for that ability as it goes on the stack. Each player may respond to this triggered ability as normal.