Bloody TendrilsFocus 3

Something of uncommon rarity requires special training or comes from a particular culture or part of the world. Some character choices give access to uncommon options, and the GM can choose to allow access for anyone. Less is known about uncommon creatures than common creatures. They typically can't be summoned. The DC of Recall Knowledge checks related to these creature is increased by 2.

An action with this trait requires a degree of mental concentration and discipline.

Focus spells are a special type of spell attained directly from a branch of study, from a deity, or from another specific source. You can learn focus spells only through special class features or feats, rather than choosing them from a spell list. Furthermore, you cast focus spells using a special pool of Focus Points—you can't prepare a focus spell in a spell slot or use your spell slots to cast focus spells; similarly, you can't spend your Focus Points to cast spells that aren't focus spells.

You must physically manipulate an item or make gestures to use an action with this trait. Creatures without a suitable appendage can't perform actions with this trait. Manipulate actions often trigger reactions.

This indicates abilities from the necromancer class.

The mindless undead you can create as a necromancer are called thralls. Spells or abilities that create thralls have the thrall trait.