Need peoples opinion on change on a spell

[richardbob123]

how game breaking would it to be to change the Summon Greater/Lesser Demon spells to summon undead

[Magzimum]

how game breaking would it to be to change the Summon Greater/Lesser Demon spells to summon undead

Regarding combat: That matters entirely on what you allow the players to summon. If the undead are of a similar challenge rating, and also remain active for a similar time, then it probably won't break the game too much, even though undead may have very different abilities and resistances than demons. You can always increase / decrease the challenge rating of the undead by giving them more damage or more HP, so that it balances.

From a roleplay point of view: Undead aren't summoned, they are usually raised. So, you need corpses. These may not always be available. This would limit things a little. But maybe in your world, undead just rise from the ground, solving this practical problem. Sometimes the storyline requires a little creativity regarding the rules, so I would just go with it.

(However, if you are a player, and not the DM, then you have to ask the DM for permission. It has to make sense in the story. You cannot point at this forum and say that "they said it's ok").