・・・。。
I get to fight monsters from all over the world, huh... My arms are itching for it.
Literal
World-throughout [genitive-の] monsters [with-と] can-fight [explanatory-の][question-か][lengthening-ぁ]... arm [subject-が] is-ringing [reflective-なぁー].
A character anticipating a video-game challenge. のかぁ extends the explanatory のか ('huh, so...?') with vowel-lengthening to convey something between marvel and mounting excitement. 腕が鳴る is a fixed idiom literally 'one's arm rings,' used to mean 'one is itching to put one's skills to use,' 'eager to get going' — the same image of restless eagerness that English captures with 'my hands are itching.' The sentence-final なぁー stretches the reflective な with the same vowel-lengthening to draw out an anticipatory tone. The reading verb 戦える is the potential form of 戦う ('to fight'), so the fight is being framed as a possibility being savored, not yet underway.