Casting below minimum range will have Undertow land that exact distance while casting beyond maximum range will have Undertow land short of it (in both cases Olaf will throw the axe in the target direction)
Passive:Olaf gains bonus armor and bonus magic resistance while Ragnarok is inactive.
20 / 30 / 40
Active:Olaf removes all crowd controls from himself. For the next 6 seconds, he becomes unstoppable and immune to crowd controls, and gains bonus attack damage. For the first second of Ragnarok, he also gains bonus movement speed when moving towards nearby visible enemy champions.
Against The Hextech Ultimatum, Olaf can't break free from the area unless he has a blink or a dash during the active duration, this because the border of the Camille's ultimate is considered to be terrain for the affected champ.