We learn of a figure of some fame, half a millennium or so ago, who was born in Llanasa: Elis Gruffydd. This gentlemen (1490 -- 1550-something) is sometimes known as "The Soldier of Calais", where he had indeed soldiered, and spent much of his life; but his essential role was as a Welsh, and Welsh-language, chronicler. He is best known for his attempted history of the world, and especially of England and Wales.
A not-quite-contemporary -- fictional -- of Elis Gruffydd, bearing perhaps a superficial resemblance to him in a couple of ways -- might perhaps be seen in the Welsh soldier Fluellen, who has a minor part in Shakespeare's play Henry V. Fluellen is reckoned by the king, and by his own comrades-in-arms, as a useful soldier; but a rather humourless and annoying know-all, given to solemnly expounding, in slightly odd English, on all kinds of things at great length. He tends toward much going-on about Monmouth -- possibly his home town?