What happens to characters which defend again an Balon attack who have a strength <5?

They do not contribute their strength, so far so good but:

Is their strength 0 ?

Is such an attack unopposed?

It doesn't reduce their strength to zero--which could potentially have some relevance if it were a Melee game with a Targ player looking to kill something with Dracarys or Plaza of Punishment.

The first sentence of the RRG for "Unopposed, Unopposed Challenge":

A challenge is “unopposed” if the defending

player counts 0 STR when the challenge winner is

determined.

The characters strength is not modified but you simply don't count them when totaling strength during challenge resolution. There are some important ramifications -

The character still has his normal strength to all other effects (such as Grey Wind or Dracarys)

If Balon's strength is reduced, a defending character may be able to count his strength (it really only matters what Balon's strength is when the outcome is being decided)

The challenge would be considered unopposed if the character isn't counting his strength and he doesn't have any other source of strength. He could, for example, county the strength from The Red Keep in order to treat the challenge as opposed.

Thx guys! So, he IS awesome. Especially in combination with his scout fleet.

Balon is a monster. I played half a dozen games with a Greyjoy fealty deck this weekend, and Balon + Great Kraken meant I was sponging up power. When Balon was killed I fished him out of my dead pile via Aeron Damphair. He's not invulnerable, but the other player found him very difficult to deal with.