I do know this one, I just found it out myself today and pieced it together from several little connections.
Apparently, it’s not so much Skaldak’s name as his rank, Grand Marshall:
The Grand Marshall was the leader of the Ice Warriors.
He was similar in appearance to Ice Lord Slaar, although he wore a more ornate helmet. He spoke normally (rather than the hoarse, loud whispers used by some Ice Warriors), as he was in ‘his own atmosphere’.
He was killed, along with the rest of the Ice Warrior fleet, when Slaar’s homing beacon was hijacked by the Second Doctor, sending them crashing into the Sun. (TV: The Seeds of Death)
So it’s possible this is the same Grand Marshall. Ice Warriors, as the name suggests, are a military race. Grand Marshall is a rank just below their Supreme Lord, akin to a Grand Admiral of a fleet. This warrior could be the previously nameless Grand Marshall from The Seeds Of Death storyline the Doctor later sends into the sun, as they live for hundred of years.
Blimey, this series really is turning into “Doctor, This Is Your Life,” huh?