Alright, I have been wondering about this situation for ages now.... and rather then continue to assume as to how the it will conclude I have deided to post the question and get some confirmation.

Archangel is attacking Beast Boy. BB's controller plays Heroic Sacrifice. Archangel's controller in response plays fastball special to stun BB. Does Archangel ready? According to the following rule, it says that if the attackers lose the attacking characteristic, then the attack concludes and does nothing. HS removes the attackers. However, FS removes the defender as well. Which ruling kicks in?

602.4 Once both players pass on an empty chain, the attack concludes. There are three different potential outcomes of an attack.

602.4a If the attacker or all attackers in a team attack no longer have the attacker characteristic, the attack concludes but does nothing.

602.4b If the defender no longer has the defender characteristic, the attack concludes and the attacker or attackers ready.

602.4c If both the attacker (or in team attacks, any of the attackers) and the defender are still part of the attack, the defending player chooses against which attacking character the defender will evaluate its ATK. (See rule 602.5.) The defending player must choose one attacker.

1) Heroic Sacrifice on chain. Another Teen Titan stunned.
2) Fastball Special on chain.

Resolve in reverse order:

Fastball special stuns defender.
Heroic Sacrifice removes attacker from the attack.

Both players pass, move to attack resolution.

Attack concludes with no attacker OR defender.

The attacker won't ready until the Attack Resolution substep, and by that time Heroic Sac has already removed the attacker from the attack.

Sigh, thought so. Darn it. Thanks anyways kairos.

Well, look on the bright side...you stunned the guy you wanted to :)

That did point out that the rules don't cover a situation where both the attacker and the defender are removed from the attack. You just have to apply both rules, and see that there is no attacker to ready anyway.

Heroic Sac

How ecactly does it work?
during declaration of attack? y or n?
when attackers are removed are they 'ready' again?

You play it during the attack.

If the attacker is removed from the attack, the attack concludes with no result.

If the DEFENDER is removed from the attack, the attack concludes with no result and the attacker readies.

Since Heroic Sacrifice removes the attacker, then during attack resolution the attack conclues with no result.