4th-level Spell: Bind Greater Fiend

Dream Magic (Conjuration)

You utter foul words, summoning one 4-Name Sword from the Underworld. You choose the Sword’s type, which must be one of challenge rating 5 or lower, such as a Shadow Demon or a Barlgura. The Sword appears in an unoccupied space you can see within range, and disappears when it drops to 0 hit points or when the spell ends.
Roll initiative for the Sword, which has its own turns. When you summon it and on each of your turns thereafter, you can issue a verbal command to it (requiring no action on your part), telling it what it must do on its next turn. If you issue no command, it spends its turn attacking any creature within reach that has attacked it.
At the end of each of the Sword’s turns, it makes a Charisma saving throw against your spell save DC. The Sword has disadvantage on this saving throw if you say its true name. On a failed save, the Sword continues to obey you. On a successful save, your control of the Sword ends for the rest of the duration, and the Sword spends its turns pursuing and attacking the nearest non-Sword to the best of its ability. If you stop concentrating on the spell before it reaches its full duration, an uncontrolled Sword doesn’t disappear for 1d6 rounds if it still has hit points.
As part of casting the spell, you can form a circle on the ground with the blood used as a material component. The circle is large enough to encompass your space. While the spell lasts, the summoned Sword can’t cross the circle or harm it, and it can’t target anyone within it. Using the material component in this manner consumes it when the spell ends.

• At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the challenge rating increases by 1 for each slot level above 4th.

Source: XGE (Conjure Greater Fiend)

• Casting Time: 1 action
• Range: 60 feet
• Components: V, S, M (a vial of blood from a humanoid killed within the past 24 hours)
• Duration: Concentration, up to 1 hour
• Ritual: No

Touch of Darkness:

• You receive the Tainted condition every time you cast this spell.

Branded

A creature who has summoned a Sword or Pentacle is branded by an infernal rune on a prominent part of their body, such as their head, chest, or back. This rune marks them as someone who has summoned a Sword or Pentacle. Communities and individuals who recognize the meaning of the rune may treat the summoner with fear, suspicion, or contempt.