Hellish Horde(Spell Compendium, p. 113)
Conjuration (Summoning) [Evil, Lawful]
Level: Cleric 9, Sorcerer 9, Wizard 9,
Components: V, S,
Casting Time: 10 minutes
Range: Medium (100 ft. + 10 ft./level)
Effect: Two or more summoned creatures, no two of which are more than 30 ft. apart
Duration: 10 minutes/level (D)
Saving Throw: None
Spell Resistance: No
A wave of spectral fire bursts forth, and out of the curling smoke steps the hunched form of a barbazu, followed by a second, and other shadowy forms loom behind them.
When the spell is complete, 2d4 bearded devils (MM 52) appear. Ten minutes later, 1d4 chain devils (MM 53) appear. Ten minutes after that, one bone devil (MM 52) appears. Each creature has maximum hit points per Hit Die. Once these creatures appear, they serve you for the duration of the spell.
The devils obey you explicitly and never attack you, even if someone else manages to gain control over them. You do not need to concentrate to maintain control over the devils. You can dismiss them singly or in groups at any time.