Here is my attempt to convert Summon Monster I to IX from 3.5e to 5e. I renamed it “Summon Creature” because I feel like it is more thematically appropriate.
1st-level conjuration
Casting Time: 1 action
Range: 60 feet
Components: V, S
Duration: Concentration, up to 1 hour
You summon an extraplanar creature of challenge rating 1/4 or lower. It appears in an unoccupied space that you can see within range. The type of the creature depends on the alignment of the caster: a good caster summons a celestial, an evil caster summons a fiend, and a neutral caster decides the creature’s type as part of the summoning. The creature will disappear when it drops to 0 hit points or when the spell ends.
The summoned creature is friendly to you and your companions. Roll initiative for the summoned creature, which has its own turns. It obeys any verbal commands that you issue to it (no action required by you). If you don’t issue any commands, it will defend itself from hostile creatures but otherwise take no actions.
The DM has the creature’s statistics.
At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the challenge rating of the summoned creature increases according to the following table.
| Spell Slot Level | Maximum Challenge Rating |
|---|---|
| 1st | CR 1/4 |
| 2nd | CR 1/2 |
| 3rd | CR 1 |
| 4th | CR 2 |
| 5th | CR 3 |
| 6th | CR 4 |
| 7th | CR 5 |
| 8th | CR 6 |
| 9th | CR 7 |
Additionally, you can summon two creatures of a challenge rating one level lower than the spell slot used, or three creatures of a challenge rating two levels lower than the spell slot used. Multiple summons roll initiative as a group, and act on the same turn.
For example, if the spell is cast using a 3rd-level slot, you can summon one creature of CR 1, two creatures of CR 1/2, or three creatures of CR 1/4.
Number Three, Never Forget 