Matthew couldn't just stand by and watch the Zhuoer Elven Army easily take down the Jackalwolf Kingdom, Caraleya.
The Zhuoer Elves' attack on the jackalweres was firstly aimed at seizing territories and secondly at obtaining more war slaves.
The strength of the Zhuoer Elven city-states depended on how many slaves they controlled.
Indeed, their own combat abilities were not bad, but given the limitations of their population and the unique internal strife of the Zhuoer Elves, one should not expect them to work together harmoniously.
After all, you can't expect a race that likes to stab each other in the back to safely entrust their own backs to their comrades.
That would be suicide!
So, when Serra was captured, the hundreds of Zhuoer Elven Soldiers under her command had dwindled to a mere twenty to thirty.
But it is also for this reason that the Zhuoer Elves possess exceptionally outstanding abilities in small-scale battles and command.