Backstabbing multiple times on the same opponent?

Question

Can a thief backstab twice if the opponent is otherwise occupied?

Scenario: Big Bob the fighter has engaged an Ogre in combat. Sneaky the thief moves silently to get behind the ogre and successfully backstabs at +4 to hit and the appropriate damage multiplier. Since the ogre is engaged with the fighter in front, can the thief 'backstab' again the next round, or is it just 'attacking from the rear' at this point?

Answer 1

From page 19 Dungeon Masters Guide:

Back Stabbing: Opponents aware of the thief will be able to negate the attack form. Certain creatures (otyughs, slimes, molds, etc.) either negate surprise or have no definable "back", thus negating this ability.

In your example, after the first attack the Ogre is aware of the thief even though he is otherwise occupied with the fighter. If the player is able to withdraw his thief and somehow cause the ogre to loose track of him, then he could get another backstab.

Remember AD&D has 1 minute combat rounds and 1 die roll is not equal one swing. Rather, it represents the total effort put forth by the monster or character for that round.

Answer 2

The thief can backstab only once in that situation, unless there's something else going on.

In the DMG, p. 19, there begins a for-the-DM discussion of the abilities of a thief. Under Back Stabbing it says:

Opponents aware of the thief will be able to negate the attack form. Certain creatures (otyughs, slimes, molds, etc.) either negate surprise or have no definable "back", thus negating this ability.

So surprise is the key ingredient in Back Stab Soup. Once the ogre is aware of the attacker, even if they can't immediately see the thief, it's not longer suffering surprise relative to the thief. Now, if that thief did something to make the ogre lose track of them so they could take them by surprise again…

Answer 3

I'm going with the "combat" tag for this answer.

Backstab is not just attacking from behind (or from a vantage point). It's waiting for the exact moment for the strike that should kill. It's the melee version of sniping.

This means the victim should not be aware of the assassin (for this is, semantically, an assassination attempt).

The moment you know some clown is playing around trying to get you, your behaviour will change.

You know that, in the melee, there are three opponents trying to get you and your group, and you move accordingly, trying to not get yourself in a stupid position). The moment you know there is a fourth opponent trying to play "ninja", your behaviour which change accordingly (moving in random ways, never losing the "ninja" from sight, and if lost, then moving against a wall, and increasing randomness of moves, etc.).

My guess is that once someone knows there are backstabbing in the melee, then there's not way to try one.

Now, if the victim believes there are only three opponents and no surprises, his/her behaviour will get more confident, taking only the three opponents into account, and open him/herself to a backstab attempt from the fourth ninja.

Now, your rules/mileage may vary.