No alliances, and none needed - their numbers are vast, dwelling deep within the mountain range. Tharis is currently unaware of the extent to which these creatures have infiltrated the mountains that line the southern reaches of their domain. The dwarves of Brynlhar in the western end of the range are quite aware, and are in a constant state of war with the orcs.
No-one knows just when this vast horde of orcs first arose; for those few sections of history that mention them, they seem to have just always been there. Rumor and legend tells of a brutal orcish warlord who united smaller clans beneath him, allowing them to flourish where they had once been scattered and weak. The tribe was named for this warlord, not by name but by his tusks, broken in his battle for supremacy over the clan, and all leaders that have followed him have taken on the same trait, in an expression of ongoing strength.
The modern tribe is a far stretch from the stupid, unplanned nature of so many orcish groups. Savage and brutal, yes, but possessed of a cunning rarely found among beastkind. The current tribe has countless orcs and a host of goblinoids in his sway, and not a few giants as well. Its spies and assassins (which number even some humans and half-bloods) stalk the lands to keep its leadership informed, which has kept it not just surviving, but thriving against foes that would otherwise wipe it out. Should the opportunity arise for them to descend upon the unsuspecting settlements nearby, it will be a bloody day indeed…