Matrim Cauthon, usually called just Mat, together with Perrin Aybara and Rand al'Thor, is a powerful ta'veren, although not as powerful as Rand.

Resolute,
Dark Friends
& Night Gathers

Fingering/4 Ply Weight 3/12nm
100g skein = ~400m/437.44yd

Steadfast,
Heart of the Dark
& Take the Black

Double Knit Weight 4/9.3nm, 14 wraps/”
100g skein = ~232m/253.718yd

Full yarn base information can be found here.

Recommended wool care can be found here.