The orthon's statblock states, "When it is reduced to 15 hit points or fewer, the orthon causes itself to explode." (Mordenkainen's Tome of Foes p. 169)

On the one hand, 0 HP is fewer than 15 HP. On the other hand, Explosive Retribution is listed under "Reactions," and you can't take a reaction when you're dead.

Is reducing the orthon from 16+ HP to 0 HP at once an effective way to prevent it from using its Explosive Retribution?

  • 1
    \$\begingroup\$ A reaction always happens after its trigger unless otherwise stated, so this would be a matter of "what happens first: the orthon taking its reaction, or the orthon falling unconscious due to dropping to 0 hit points?" I'm not sure, so I'll leave this here for others to use. \$\endgroup\$ Oct 25, 2020 at 19:51
  • \$\begingroup\$ A question with a similar question buried in it: "Can a Mace of Disruption kill a Vampire with its ability?" \$\endgroup\$ Oct 25, 2020 at 20:13

1 Answer 1


The reaction would not go off

The general rule, from page 252 of the DMG is as follows:

If a reaction has no timing specified, or the timing is unclear, the reaction occurs after its trigger finishes, as in the Ready action.

A similar rule is in Xanathar's Guide to Everything:

the reaction happens after its trigger completes, unless the description of the reaction explicitly says otherwise.

The trigger, in this case, is the orthon dropping below 16HP. If it drops to 0HP, it immediately falls unconscious. The unconscious condition includes the incapacitated condition, which in turn includes an inability to take reactions. Therefore, when the trigger is finished, the orthon no longer has the ablity to use its reaction.

Note that the above rule is specifically invoked in case of an unspecified and/or unclear timing. I certainly think this is the case.

Perhaps Explosive Retribution makes more sense as an innate ability, such that a sufficiently damaged orthon automatically explodes, in which case dropping it to 0HP would not prevent the ability from triggering. However, RAW it is listed as a reaction.

Therefore, I would consider an exploding 0HP orthon to be a deviation from RAW, but not necessarily a bad one.

  • \$\begingroup\$ One really wonders why that bit about reactions is not under the Reaction paragpraph in the PHB. \$\endgroup\$ Oct 25, 2020 at 21:18
  • \$\begingroup\$ Indeed, I remembered reading it somewhere so I searched through the PHB first... For whatever reason, both the DMG and Xanathar's have it (the latter I'll edit in). \$\endgroup\$
    – ADdV
    Oct 25, 2020 at 21:54
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    \$\begingroup\$ You might also compare to the Nurtured One of Yurtrus, which also explodes but has its ability listed as a Trait instead of a Reaction, to allow it to blow up at 0 hp. \$\endgroup\$
    – Erik
    Oct 26, 2020 at 7:57
  • \$\begingroup\$ Nah. I've seen people intentionally draw AoO from wounded orthons so they can't explode because of a lack of reactions. Making them explode without needing a reaction unbalances their CR. \$\endgroup\$ Oct 26, 2020 at 13:20

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