Third Sigil of Pestilence

When you cast this spell you must target a creature that is missing any of its Hit Points. They must make a Strength Saving Throw. On a success, this spell has no effect. On a failure, the target becomes Restrained and takes 3d10 Piercing Damage.  Once Restrained, and later using your bonus action, You activate the Sigil: 

Choose a number of creatures equal to or lower than your proficiency bonus that are within 60 ft of the target of this spell. The chosen creatures are attacked with the First Sigil of Pestilence using the target of the Third Sigil of Pestilence as if you were casting the spell from their location.

An infected creature can make an additional Strength Saving throw at the end of each of its turns. On a success, they are no longer affected by the spell. While concentrating on the spell you can use your Bonus Action to activate the Sigil again,

If you are concentrating on the spells First Sigil or Second Sigil of Pestilence when you cast this spell you are counted as concentrating on all Sigil spells at once.