These elves not only hurt Chieng to such a brutal extent, but they were also holding his wife captive. That was what they came here to say.
Given these facts, retaliation was inevitable, but Tristan needed to be smart about this. He believed that if he were to reject their offer, the elves would make trouble right away. He needed to calculate the risks of bringing a sudden battle to the streets of Caerleon.
With a quick scan, he could see that these elves were more or less on the same level with the Vanyar elf warriors, at least in terms of strength.
Each of them possessed around 75 points of battle power and 125 in terms of spirit force. All 50 of them running amok in his town would be problematic, to say at the least.
The fact they were still mounted on their horses also gave them the advantage right now. They could make a swift getaway if the situation did not turn in their favor.