The clan chieftain's own.
A chieftain's fighting court of professional warriors, like the levied men beneath them, supplied their own equipment. They were wealthy enough to, as a rule, wear armor from head to toe: either a skin of mail, or a foreign-made set of plate armor. Unlike the upper classes in more foreign countries, though, they habitually fought on foot. The broken terrain of the Ebon Forest both better befitted dismounted combat, and the cost of outfitting a man with head-to-toe armor was heavy enough without throwing in a fine war elk and its barding. (No retainer would show up for muster with an exposed hair; such a thing would invite ridicule; so if they could not afford an elk and mail skin at the very least, they would go without the elk.)
The chieftain's inner circle--his personal bodyguards, thanes, advisors and friends--were above this rule. In return for their gift of total loyalty to him, he was expected to gift them their equipment out of his own pocket. That meant that every one of his chosen could fight mounted.
This chosen warrior is armed with an especially long falx astride his barded mount. Because the Ebon Forest does not often feature a good flat field on which to charge, he is kitted out instead for extended close combat: to get stuck in and then lay about, hacking at the bare-chested masses trying to bite his elk's tendons.