Summoning arbitrary monsters

[GilesTheCleric]

The Celestial Summoning Specialist feat says:


Normal: Without this feat, adding a creature to your summoning list requires you to remove one that is already on the list.

Where can that rule actually be found? It's not in the PHB, unless I'm looking in the wrong place.

[Cosi]

I believe there are some monsters in later Monster Manuals that may be added to the summon monster list in place of monsters that are already on it. For example, per page 35 of the Monster Manual III, an evil spellcaster can opt to give up the ability to summon a babau with summon monster VII to instead summon an Arrow Demon with the spell.

[Florian]

Wrong place. The individual new summon options always called out to replace one on the list. Look up Fiendish Codex II or Stormwrack for examples.

[Big Fau]

The Celestial Summoning Specialist feat says:



Where can that rule actually be found? It's not in the PHB, unless I'm looking in the wrong place.

IIRC, its in the DMG.