Standard action spells
Casting a summoning spell generally requires a standard action. The creature(s) you summon appears next to you, though feats or powers might enable you to summon it nearby instead.
Spell or creature
When a summoning spell is cast, it’s definitely a spell. After casting the spell, a summoned creature is a creature.
There are four types of summoned creature. Elementals and beasts summoned by druids, undead summoned by necromancers and demons summoned by demonologists are all superior creatures. Superior creatures take their turns like any other creature without needing to be controlled.
A summoned creature fights for you until the end of the battle or until it drops to 0 hit points. At 0 hp, summoned creatures are slain and removed from the battle.
One summoning spell at a time
Each spellcaster can have only a single summoning spell active at a time. If all the creatures from an earlier summoning spell have been slain, you’re free to cast another. Alternatively, you can dismiss your own previously summoned creatures as a quick action to clear the way for a new summoning spell.
Summoned creatures are not the same as real creatures. They’re partly real, partly magical. Their abilities don’t always match the capabilities of the creatures that the adventurers encounter for real. Sometimes this is reflected in a summoned creature’s attacks or abilities. It’s always reflected in a summoned creature’s hit points.
Each summoned creature stat block indicates its base hit points. Starting hit points for summoned creatures are nearly always lower than hit points for non-summoned versions of the same creature. Some class feats might increase the hit points of summoned creatures.
The turn you summon a creature, that creature takes its turn immediately after your turn in initiative order. The summoned creature continues to take its turn immediately after you (even if your initiative order changes) until the end of the battle.
You can mix the actions together if you want, but if the GM decides it’s confusing or the rules are starting to have conflicts, the GM can enforce the ‘proper’ turn order.
(Superior creature) During its turn, the summoned creature can act like any other creature, taking a standard, move, and quick action.
Magic item bonuses
Summoned creatures use the default bonuses of their summoner’s magic weapon or implement, if any. In other words, if you have an attack and damage bonus from a magic weapon or implement, so do any creatures you summon.
Similarly, summoned creatures use the default bonuses of their summoner’s armor, cloak, and and head items, if any. In other words, default bonuses to AC, PD, and MD from magic items also apply to your summoned creatures.
This only applies to default bonuses. Bonuses and abilities that come along with an item that are not default bonuses only apply to summoned creatures if they specify that. At present, not many do.
As a rule, summoned creatures don’t benefit from the escalation die. A summoned creature can add the escalation die to attacks, however, if you use a quick action to give it orders or magical reinforcement. The summoned creature then gets to use the escalation die until the start of your next turn, including for opportunity attacks and other attacks that it gets to make during other creatures’ turns.
For example, during the turn you summon the creature, you use a quick action afterward to give it orders, allowing it to use the escalation die bonus. At the start of your next turn, the creature no longer gets to use the escalation die, so you’ll have to use another quick action again during that turn for the creature to keep getting the benefit.
If you’ve summoned a mob of mooks, a single quick action lets every member of the mob use the escalation die.
Summoned demons use the escalation die.
Summoned creatures generally count as your allies.
You can choose to treat them as non-allies when that’s better for you. For example, when a monster’s attack is against one of its random enemies, it’s good for you to have your summoned creature count as an ally of yours and an enemy of the monster. But take the case of the bard’s 3rd level spell, wild heal. Odds are the bard PC in your group doesn’t want to have to include your summoned creature as one of the random allies that might get to heal, so they can choose to ignore your summoned creature as an ally.
No recoveries, bad healing
Druid, necromancer: Summoned creatures don’t have recoveries. If you cast a healing spell on a summoned creature that requires the use of a recovery, the summoned creature heals hit points equal to your level. If you use an effect that would heal a summoned creature without using a recovery, the summoned creature only heals half the normal hit points of the effect. Temporary hit points still work normally.
Demonologist: Unlike other summoned creatures, demons summoned by demonologists can’t heal.
No nastier specials
Creatures you summon don’t use nastier specials.
Druid, Necromancer: You can dismiss your summoned creature using a quick action.
Demonologist: Dismissing a demon during combat isn’t that simple: after dismissing the demon, roll a control save as if the demon had dropped to 0 hit points. If the demon goes out of control, use its current hit points or the amount it would have if it dropped to 0 and then went out of control, whichever is higher. Out of combat, you concentrate fully and dismiss your summoned demon without rolling a control save.