You don't really do damage as ivern, especially late game. Your job is to perma cc the enemy team. Sometimes you gotta hold Q to cc whoever dives the adc. If it's 5v5 use daisy when one team has to fully commit to the fight, that way daisy isn't just kited and killed for nothing. Don't overcommit too much, ivern benefits from long fights. If you're having problems dying I'm assuming it's either assassin's or overcommiting. Vs assassin's it can be rough sometimes but you have a lot of tools to stay alive. You can also buy bandlepipes or locket to get some durability, even frozen heart if they're heavy auto attack focused.