I'm like 60% sure there is a Pokemon whose attacks hurt souls but until I find that Pokemon I'll drop my argument for Endure. But even without Endure, Riolu can still use Quick Guard to block sans attacks or use Detect and precognition to dodge.
Luckily for you, I've been studying Pokedex entries to find out which is the least intelligent Legendary so as to determine Pokemon candidates for the
Most Unintelligent Characters for Every Tier thread!
Heck, just in general I read a lot of Pokedex entries.
For what its worth, though, there are no Ghost-type Baby Pokemon, & Baby Pokemon are most of what Riolu scales to. I forget if Aura works on ghosts, but at least some types of it might.
Spectrier is a Legendary Pokemon that can affect the soul with its attacks:
| Sword | It probes its surroundings with all its senses save one—it doesn’t use its sense of sight. Spectrier’s kicks are said to separate soul from body. |
|---|
Cursola, evolved from Galarian Corsola is a fully evolved 2nd stage Pokemon:
| Sword | Its shell is overflowing with its heightened otherworldly energy. The ectoplasm serves as protection for this Pokémon’s core spirit. |
|---|
| Shield | Be cautious of the ectoplasmic body surrounding its soul. You’ll become stiff as stone if you touch it. |
|---|
Bramblin is a 1st stage Pokemon:
| Scarlet | A soul unable to move on to the afterlife was blown around by the wind until it got tangled up with dried grass and became a Pokémon. |
|---|
Chandelure is a fully evolved 3-stage Pokemon:
| White | Being consumed in Chandelure’s flame burns up the spirit, leaving the body behind. |
|---|
Spiritomb is a single stage Pokemon:
| Sword | Exactly 108 spirits gathered to become this Pokémon. Apparently there are some ill-natured spirits in the mix. |
|---|
| Shining Pearl | It was bound to a fissure in an odd keystone as punishment for misdeeds 500 years ago. |
|---|
Red Flower Florges is a form of Florges, a fully evolved 3-stage Pokemon:
| Violet | They say that flower gardens created by Florges are constantly showered with a power that can heal both body and spirit. |
|---|
This entry of Florges's, however, could be euphemistic, however, &/or refer to emotions &/or mental health rather than spirituality, however.
There might be others I haven't considered. Plus there's stuff like some Ghost-types, such as Honedge, being stated to drain "life force" or "life energy" or such, but that may be separate stuff.
Hopefully this helps reach a conclusion.
Also, caution that I'm not sure if all of these have profiles on VSBW yet.