Patryn of Elvenshae
Which is funny, because of the four things you listed, only half are actually damage. The other two are not damage.
EDIT:
Note that damage is actually a well-defined game term, being a reduction in hit points or in an ability score. Anything which does not do either of those has not actually done damage.
And yet, RAW- "When your attack succeeds, you deal damage." PHB p134.
Yes... I know that farther down the page, you get "Damage reduces a target's current hit points."
But all that just gets us to this point:
When your attack succeeds, you deal damage. (Rule)
Damage reduces a target's current hit points. (Lemma)
A successful trip attack results in the target being tripped.
Nowhere in the trip attack rules (PHBp158) does it state that a trip attack does or doesn't do damage... so either trips do normal damage for the method in which the trip is delivered OR (see
Conclusion below).
And:
When your attack succeeds, you deal damage. (Rule)
Damage reduces a target's current hit points. (Lemma)
A successful Vorpal attack results in the target being beheaded.
Nowhere in the Vorpal attack rules (DMGp226) does it state that a vorpal attack does or doesn't do damage... so either vorpal attacks do normal damage OR (see
Conclusion below).
So we have a conundrum.
Conclusion- Either not all successful attacks deal damage- contradicting the
very first Rule under the Dealing damage section, and thus the RAW- or the Lemma is false, also contradicting the RAW.
Furthermore, the PHB only has 2 definitions of death- reduction to -10 hp or death by massive damage (50+points in a single strike followed by failing a Fort save); the DMG adds the reduction of Con to 0, Death Attacks, or death by accumulation of negative levels.
And even then, the DMG (p292) states "In case it mattes, a dead character, no matter how he died, has -10 HP," thus collapsing all definitions of death into the first one.