frost titan rulings who controls ability ley line magic

[F16]

I have a ley line in the battlefield

other player has a frost titan

at the beginning of his upkeep, who controls the ley line ability, me or him? would the frost titan first ability trigger if he tries to put counters on it?

[Arix]

Ley Line's controller controls the ability.

[kevin]

wait, so who has to pay the 2 mana so that spell wont be countered, the controller of the ley line or the controller of the frost titan? Am thinking the controller of the frost titan as why would the controller of the leyline want to pay so that other player gets to put counter on his creature

[Arix]

As I said, the controller of Ley Line is the controller of the ability. Therefore, that player has to pay 2 or the ability will be countered.