Interesting topic. I always thought that nothing could be stronger than a black dragon. However, in a one-on-one fight, the Titan wins about 8 out of 10 times. Its damage can vary greatly; once, it dealt 87 damage in a counterattack. If the dragon waits in the first round, the Titan wins easily. If the dragon attacks immediately, the Titan retaliates much more strongly. On its turn, the Titan simply attacks the dragon. Almost always, after the first round, the dragon has less than half its health remaining, while the Titan has more than half. After that, the dragon doesn't have much of a chance. If it waits, the Titan will happily attack it again, and the difference in HP will increase even further. After that, if the dragon attacks the Titan, it will most likely die from the counterattack. So, the question can indeed be posed this way: what are the dragon's chances of surviving to the third round? Personally, once it had 11 HP left after two rounds (the Titan had 34), and another time it had 2 HP. In the other battles, the Titan defeated the dragon in 2 rounds.
Amazing! I have to vote for the Titan, although initially, without any empirical evidence, I was going to vote for the Black Dragon.