How does the eldritch invocation "Repelling blast" affect a bigger creature?

Question

I am currently playing as Melkor, a young warlock who uses his eldritch blast in pretty much every fight.

Since Melkor is level 7, he has access to 4 eldritch invocations. One of them is Repelling Blast, which is described as follows:

Repelling Blast

Prerequisite: eldritch blast cantrip

When you hit a creature with eldritch blast, you can push the creature up to 10 feet away from you in a straight line.

Recently, Melkor and his group have encountered a Hill Giant. A hill giant is huge. During the fight, it had a hard time getting close to the group, being pushed 20 feet per round (2 blasts).

My DM was not really happy with the fact that my medium human warlock was able to simply "shoo away" his giant. He seemed to say that it was not logical that in the event of me being near a dragon turtle, I could push it away with a boosted cantrip.

So, my question is: How does the eldritch invocation "Repelling Blast" affect a bigger creature?

Is there a general rule for this kind of spell?

Answer 1

It works just like you've been using it: the invocation doesn't care about creature size, and will make the Blast push it 10′ away. Logic agrees perfectly: it's magic and that's what it's supposed to do, so the magic does that.

There are much more powerful effects than Repelling Blast that can mess with a DM's darling plans. They're just going to have to accept that this can be an effective way of dealing with single large melee creatures, adjust, and get creative. (If the DM is reading, I suggest the giant start throwing trees and pieces of mountains at the warlock. That would be one of the giant's logical responses, after all.)

Answer 2

@SevenSidedDie has adequately answered the core question. But there also seems to be a question here about the power level.

My DM was not really happy with the fact that my medium human warlock was able to simply "shoo away" his giant. He seemed to say that it was not logic that in the event of me being near a dragon turtle, I could push it away with a boosted cantrip.

So the Hill Giant is CR5 and your party is level 7. On average, this was going to be a walk in the park. He has low AC, low Int and limited defenses. At your level, the Hill Giant is mostly just there to protect a bigger villain by absorbing damage. On his own, he's not really supposed to be a threat.

Yes, it's mildly annoying that Eldritch Blast was so effective, but it's also your explicit specialty. Warlocks trade of lots of spell access in order to get a pretty significant Eldritch Blast. Honestly, an Archer at that level (Fighter or Ranger) would have equal damage, better odds of hitting and increased range (120/600). A party with an Archer would likely have been able to "run & shoot" the Hill Giant to death without ever engaging directly.

Answer 3

The accepted answer is correct, but regarding the logic of it, here's how I explain it in my campaign. Note, this is just for flavor, it doesn't change RAW.

Consider:

• The effect only works on creatures, not objects.
• The target doesn't get a strength save.

This suggests the effect of the "push" is not just straight force, but rather something more subtle. My interpretation is that the spell makes the target briefly insubstantial... almost massless. They are then carried along with the energy of the spell for 10' or until they encounter a solid object. At that point they regain mass and stop moving. Under this interpretation the spell performs exactly as written... the subject is pushed back, but there are no secondary effects. They won't take damage from hitting an object, they won't be knocked prone, they can't hurt anyone else by running into them.

I think this helps address the apparent illogic of affecting creatures of any size, but also limits the power by ensuring it only behaves exactly as written: "the creature is pushed back up to 10'".

Answer 4

Repelling Blast lets you push anything away 10 feet, one way the change the system I see is to compare the targets strength mod with your charisma mod and on a lower strength mod they are pushed away, otherwise they just take damage, but this would only work with larger creatures because it would suck all the efficiency of the Invocation otherwise