Summon Gnoll

Riga believes it summons a Gnoll Spirit from the Abyss, but she suspects the spell's restraints work by basically creating a blank slate personality and memory once its summoned, so it shouldn't retain anything from the Abyss or from its time in the Material.

However. You can summon the same spirit again and it will retain experiences from working under you while summoned.

Summon Gnoll

Level 3 Conjuration. (Warlock, Wizard, Cleric)
Casting Time: Action
Range: 90 feet
Components: V, S, M (a lump of flesh)
Duration: Concentration, up to 1 hour

You call forth a Gnoll spirit. It manifests in an unoccupied space that you can see within range and uses the Gnoll Spirit stat block. When you cast the spell, choose the creature's form: Rampager, Channeler or Stalker. The spirit resembles a Gnoll with the chosen form, which determines certain details in its stat block. The creature disappears when it drops to 0 hit points or when the spell ends.

The creature is an ally to you and your allies. In combat, the creature shares your Initiative count, but takes its turn immediately after yours. It obeys your verbal commands (no action required by you). If you don't issue any, it takes the Dodge action and uses its movement to avoid danger.

Using a Higher-Level Spell Slot. Use the spell slot's level for the spell's level in the stat block.

Gnoll Spirit

Medium Fiend, Neutral Evil
AC: 11 + spell level (natural armor)
HP: 40 (Rampager only) or 25 (Stalker only) or 20 (Channeler only) + 10 for each spell level above 3
Speed: 30 ft., climb 20ft (Stalker only)
Str: 14 (+2) Dex: 14 (+2) Con: 15 (+2) Int: 10 (+0) Wis: 12 (+1) Cha: 7 (-2)
Condition Immunities: exhaustion, frightened, charmed
Senses: darkvision 60ft., passive Perception 11
Languages: Abyssal, understands all languages you speak
CR: None (XP 0; PB equals your Proficiency Bonus)

Traits

Hunger of Yeenoghu As an action or as a bonus action immediately after reducing a creature to 0 HP, the Gnoll Spirit can consume the flesh of a corpse within 5 feet of it. It regains 1d8 + its CON modifier hit points. Consuming the corpse in this manner magically destroys it, leaving behind any equipment it was carrying.

Actions

Multiattack The Gnoll Spirit makes a number of attacks equal to half this spell's level (rounded down).

Threatening Claw (Rampager Only). Melee Attack: Bonus equal to your spell attack modifier, reach 5 ft. Hit: 1d10 + 2 + the spell's level Slashing damage, and the target has disadvantage on attack rolls against any creature other than the Gnoll Spirit until the end of its next turn.

Haunting Witherlings (Channeler Only). Ranged Spell Attack: Bonus equal to your spell attack modifier, reach 120 ft. Hit: 1d8 + 2 + the spell's level Necrotic damage and the creature is Frightened of the Gnoll Spirit until the end of its next turn.

Far-Fang Bolt (Stalker Only). Ranged Attack: Bonus equal to your spell attack modifier, reach 150 ft. Hit: 2d4 + 2 + the spell's level Piercing damage and the Gnoll has advantage on Wisdom (Perception or Survival) checks to find or track the target for the next hour.