Board Thread:General Discussion/@comment-5621713-20121107215504/@comment-24367109-20140101202805

Since Merlin is the last Dragonlord, he's able to summon Aithusa. And, once a dragon has been summoned by a Dragonlord, the dragon must obey the Dragonlord, so Merlin could easily have had involvement with Aithusa. However, getting involved with another dragon is risky, after what happened with Kilgarrah.