Can spells or spell-like abilities do non-lethal damage?

Question

I'm working on a Paladin/Warlock combination, based off of Pureferret and Miniman's work, and as part of this, I noticed Miniman's remark that Repelling Blast won't be that useful, because as a Paladin, you want people up close and personal when you're in a combat situation, not further away.

However, as a Paladin, your creed sometimes leads you to not want to engage in full-blown combat with a potential adversary -- you may want to drive them off or incapacitate/capture them instead. With this, I wonder: can Repelling Blast, or other spells and spell-likes (such as invocations), be made to do non-lethal damage? If so, I'm thinking that it'd be useful in exactly that sort of situation -- halting someone/pushing them away without having to wade into a melee with them or blow them to smithereens.

Answer 1

No, Repelling Blast cannot be used to deal non-lethal damage.

Only melee attacks are able to deal the non-lethal damage required to knock out and automatically stabilize a creature.

PHB page 198, under "Knocking a Creature Out", states:

When an attacker reduces a creature to 0 hit points with a melee attack, the attacker can knock the creature out. The attacker can make this choice the instant the damage is dealt. The creature falls unconscious and is stable.

However, you should talk to your DM about allowing your Paladin/Warlock to perform Medicine checks to stabilize creatures post-combat.

Many DMs rule that being reduced to 0 HP results in instant death for unimportant enemies, but if you explain your intent to your DM they may allow the enemies you 'kill' to start making death saving throws instead and provide a chance to be stabilized, the same as PCs and important NPCs.

Answer 2

Only spells/abilities that include a melee attack can knock a creature out

First, a note: there is no such thing as "non-lethal damage" in 5e. Instead there is a rule called "knocking a creature out" which is the only way to do damage without killing a creature that the rules provide.

Sometimes an attacker wants to incapacitate a foe, rather than deal a killing blow. When an attacker reduces a creature to 0 hit points with a melee attack, the attacker can knock a creature out. The attacker can make this choice the instant that damage is dealt. The creature falls unconscious and is stable.

As you can see the rule provides that you can knock a creature out as long as you are performing a melee attack.

Melee attack is a general category including melee weapon attacks as well as melee spell attacks. If a spell includes a melee spell attack, you can choose to apply this rule.

For example, the spell steel wind strike says:

Make a melee spell attack against each target.

Thus, you could apply the rule for knocking a creature out to those attacks. Also worth noting that this spell affects multiple targets. That doesn't matter; as long as it does melee attacks you can choose to knock them out.

Repelling blast won't work

Something like Repelling blast cannot knock a creature out however since it does not involve a melee attack. Repelling blast simply modifies eldritch blast which says:

Make a ranged spell attack against the target.

Since it uses ranged, not melee, spell attacks you cannot choose to knock a creature out with it.

Answer 3

There isn't a concept of "non-lethal damage" in 5e; instead it has:

Sometimes an attacker wants to incapacitate a foe, rather than deal a killing blow. When an attacker reduces a creature to 0 hit points with a melee attack, the attacker can knock the creature out. The attacker can make this choice the instant the damage is dealt. The creature falls unconscious and is stable.

The requirement here is for a melee attack. So if your spell uses a melee spell attack, for example, Shocking Grasp, then you can knock an enemy unconscious with it. For Eldritch Blast specifically, since it uses a ranged spell attack, you can't knock enemies unconscious with it. The Repelling Blast invocation doesn't change this, obviously, since it just modifies your Eldritch Blast to push people in addition to its normal effects.