The counterpoint to the imp; there are no monsters that are a good counterpoint to the imp in D&D and its ilk. There are lantern archons, and other such beings, but nothing really comes close to an iconic creature that would serve as the mirror to the imp the way that some angels have equals among the higher ranks of demon kind.
So here is the Ishim.
Small Celestial, lawful good
Armor Class 13
Hit Points 11 (2d6 + 4)
Speed fly 40 ft. (hover)
Str 4 (-3), Dex 17 (+3), Con 14 (+2), Int 11 (+0), Wis 13 (+1), Cha 14 (+2)
Skills Intimidation +3, Insight +3, Persuasion +4, Stealth +5
Damage Resistances lightning; bludgeoning, piercing, and slashing from nonmagical attacks
Damage Immunities fire, radiant
Condition Immunities deafened, exhaustion, poisoned, prone, restrained
Senses blindsight 120 ft., passive Perception 11
Languages Celestial, Common
Challenge 1 (200 XP)
Messenger. The ishim is the messenger for the divine host, and projects its voice magically to all who can hear within 100 feet. The ishim has advantage on intimidate checks when it uses its booming voice.
Magic Resistance. The ishim has advantage on saving throws against spells and other magical effects.
Tongue of Flame. The ishim can speak and understand any language. Additionally, it has an aura that grants this ability to any creature within 50 feet that can speak and understand a language.
Divine Flame. Ranged Attack: +5 to hit, range 30 ft., one target.Hit: 13 (3d8) radiant damage.
Divine Speech (Recharge 6). The ishim utters a holy phrase. Enemy creatures within 100 feet must make a DC 13 Wisdom saving throw, becoming frightened for 1 round on a failure. Creatures that fail this saving throw by 5 or more are frightened for 1d4 rounds.
Invisibility. The ishim magically turns invisible until it attacks or until its concentration ends (as if concentrating on a spell).
An Ishim appears as a small glowing halo, sometimes literally a golden shining hoop, at other times as a glimmering mandala of symbols and numbers, but always with a golden light. Though small, the light it sheds makes it appear larger or at least more imposting.
The ishim is an exalted celestial creature that occupies the third sphere. They are the divine messengers, and are either born into existence by divine will, or are the exalted souls of righteous men of piety. Ishim are just as likely to deliver a word of warning to a man about to commit a grievous sin as they are to warn a city of impending catastrophe. Their minds are mysterious, following the vaulted edict of the diving host, and rarely speak outside of their intended message.
In rare situations, a person is deemed to have a pious destiny may have an ishim granted to them, in which case the ishim becomes a doting mentor and guardian. Such cases are exceedingly rare, and recipients of this mentorship are usually cloistered by mortal agents seeking to protect the individual.