Can you still use your bonus action and/or reaction when under the effect of a berserker weapon?

Question

When attuned to a Berserker Weapon, if you receive damage and then fail a DC 15 Wisdom saving throw, you go berserk and must use your action to attack the nearest creatures (friend or foe), moving to the next creatures once the nearest ones are defeated. This therefore locks your action and movement.

But what about your bonus action and reaction? Let's say, for example, that I'm a Level 7 Redemption Paladin in berserk mode but with an Aura of Vitality, could I use my bonus action to heal my ally after the first hit, then use my reaction to take the damage instead of him (Level 7 Redemption Aura) on the second hit ?

Answer 1

Berserker weapons do not restrict how you use your bonus action

Rules as Written and Rules as Intended agree: you can use your bonus action freely while berserking.

While berserk, you must use your action each round to attack the creature nearest to you with the axe. If you can make extra attacks as part of the Attack action, you use those extra attacks, moving to attack the next nearest creature after you fell your current target.

Even though bonus actions are just a special type of action the fact that the item says "action" (singular) instead of "any actions you have" or "your full turn" means that it is only intended for the weapon to take up your one normal action each turn.

Also, the wording assumes that you are able to attack with this action every turn, this is not at all true of a bonus action in general and is more support that bonus actions were not intended to be included in the curse effects.

Jeremy Crawford explicitly supports this interpretation:

Q: Regarding the Berserker's axe, when berserking is triggered, can the player still use his move and bonus on his turn or no?

A: The berserker axe doesn't prevent a bonus action, and you can move freely if you fulfill the attack requirement.

This also means that once you have moved and attacked you can move as you will as well.

But your proposed use of a bonus action still would not work

With an Aura of Vitality, could I use my bonus action to heal my ally after the first hit[?]

Jeremy Crawford has clarified:

No general rule allows you to insert a bonus action between attacks in a single action. You can interrupt a multiple-attack action with a bonus action/reaction only if the trigger of the bonus action/reaction is an attack, rather than the action.

You are taking the Attack Action and getting multiple attacks from the Extra Attack feature. However, you cannot insert a bonus action into the middle of another Action unless the bonus action says you can. The aura of vitality bonus action does not say so therefore you cannot do this.

However, you would be able to use the bonus action after your attack action was complete.

Reactions work as normal

[Could I] use my reaction to take the damage instead of him on the second hit?

Reactions are separated from actions and thus are unaffected completely by the curse's requirements.

For this case specifically, Aura of the Guardian states:

When a creature within 10 feet of you takes damage, you can use your reaction to magically take that damage, instead of that creature taking it.

Since the trigger is taking damage, you can indeed transfer the damage onto yourself. You could even use this reaction between attacks if you wanted (unlike the bonus action heal as described above).

Answer 2

RAI: You are free to use your Bonus Action and movement

Jeremy Crawford has given his input:

The berserker axe doesn't prevent a bonus action, and you can move freely if you fulfill the attack requirement.

I believe his Intent is different than RAW below and that's okay and it can be up to the table/DM to go with RAW or RAI.

However, you must still fulfill the attack requirement (complete all attacks) before you can use that Bonus Action freely. In your scenario, your Redemption Paladin would move to the nearest opponent, take their Attack action (includes attack and extra attack), and then you can your reaction (after the extra attack)/bonus action/remaining movement.

RAW: Bonus Action and Reaction must attack (if available)

Berserker's gonna go Berserk. The curse seems clear in that when under the curse of Berserk, all you want to do with your action choices is attack with the axe.

Bonus Action

The Berserker Axe stipulates (emphasis mine):

While berserk, you must use your action each round to attack the creature nearest to you with the axe. If you can make extra attacks as part of the Attack action, you use those extra attacks, moving to attack the next nearest creature after you fell your current target. If you have multiple possible targets, you attack one at random.

The bolded section only states that you must your action to attack the nearest opponent. The question now is are Reactions and Bonus Actions considered actions.

Bonus Actions

Bonus actions are a type of action, as explained in the PHB (189):

Anything that deprives you of your ability to take actions also prevents you from taking a bonus action

Since the Berserker Axe requires you to use your actions to attack, then should you have a Bonus Action that is an attack, you must use it attack.

What if you don't have a Bonus Action attack?

Unfortunately, it doesn't really matter. The Bonus Action is still an action, and if you can't attack with it, you still can't use it because you must use your action to attack with the axe.

Reactions

We can look to the Incapacitated condition to get some guidance here. Being Incapacitated (PHB, 290) details:

An incapacitated creature can’t take actions or reactions.

The separation of those two things suggests that they are different and that a Reaction is separate from an action.

However, the PHB (page 190) does clearly state:

Certain special abilities, spells, and situations allow you to take a special action called a reaction.

This is pretty strong evidence that a reaction is an action as well.

Note: I still think it's weird that you have your choice of Reaction here. If you're Berserk and attacking whatever is closest to you with your action, then why would the Reaction not be included in your Berserker state?

Because of that clause in the PHB about special action and the above that it just doesn't make sense thematically, I don't think you'd be able to use your reaction in any way except to attack.