Playing the Sudden Osprey card

[Unguided]

I have one question about defending parties as pertaining to Sudden Osprey.

For those who are Unfamiliar with it, the card text says
You may play this card whenever you could play a tactic
When this card enters play, you may pick a character. If you do, that character gains 1 strength and 1 life this turn.

Now, I want to know if one of the correct ways to play it is to use it in response to an attacking party when I have no defending characters and then have it defend with the +1 life and strength bonus from its ability.

[SubtleThunder]

from the rulebook:


How to Attack
1. Pick a faction or location you do not control. Announce you are attacking that faction or location. If a
player forgets to announce what they are attacking then by default they are attacking their
opponent’s faction.
2. Pick one or more non-depleted characters you control to form an attacking party. Deplete those characters.
(To attack, a character must have been in play under your control since the start of the turn.)
3. You can play tactics or use abilities any number of times.
4. Your opponent can play tactics or use abilities any number of times.
5. Your opponent picks any number of non-depleted characters they control to form a blocking party.
6. Resolve the battle. (see “How to Resolve a Battle”)

You can play Osprey during step 4, and then form a blocking party with it.

Also, Osprey can pick itself for its ability.