Shaelmaar from the Emperor of Nilfgaard was the carefully bred shaelmaar that Emhyr var Emreis gave to Anna Henrietta and the folks of Toussaint as a form of entertainment to put in the arena. He later went to have a mate sent over, though the other shaelmaar panicked aboard the ship and wreaked havoc, sending the ship and beast to the bottom of the ocean.
Combat tactics are the same as a classic shaelmaar.
Gladiator fights in massive arenas are a popular form of entertainment in Nilfgaard. Usually the fighters are slaves specially trained for this purpose, yet at times the arena masters pit humans against monsters. The shaelmaar Geralt had to fight in the tourney grounds was a present from the emperor to his relative, Duchess Anna Henrietta. It had been caught while young and prepared for its ultimate purpose by Nilfgaardian trainers. That does not mean it was tame, however – in fact, its wildness and inborn ferocity had not been dulled one whit. Like all creatures of its species, it was blind but could unerringly pinpoint its opponents' location using echolocation. The shaelmaar had thick armor and near impenetrable skin. It could also roll into a ball and charge its opponents. Its underbelly, however, was relatively vulnerable and became exposed when its charge failed.
If Geralt kills it:
In the end, though the fight was long and difficult, Geralt defeated the shaelmaar and, when the duchess called from the stands for him to finish the beast off, he duly dealt the final blow.
If Geralt spares it:
In the end, though the fight was long and difficult, Geralt defeated the shaelmaar and, when the duchess called from the stands for him to finish the beast off, he refused to kill the creature, not wanting to take a life merely to amuse a crowd.