"Are you a summoner?" Bai Xun posed a question, upon spotting the thunder lion, which was constantly absorbing ether energy from Mark.
This is the difference between a summoned beast and a tamed beast.
The tamed beast or mount is independent of its own ether energy but it stays and sleeps at a stable just like others. If it dies, then, it dies.
On the other hand, a summoned beast of a summoner is immortal. Even it dies in battle it will be resurrected after a couple of days. It also resides within the mindscape of its host but the manifestation of its physical body will consume ether energy from its host/master.
This is why Bai Xun was sure that Mark is a summoner. Despite not being able to sense ether energy, he had his suspicions about it, mainly because of how he constantly takes a huge tank out of nowhere.
Now, he confirmed it.
