Who orders triggers MTG?

This is the general rule: when the same event triggers multiple triggered abilities, the controllers of the abilities decide what order to place them on the stack, in APNAP (active player first, then non-active player) order (rule 603.3b).

Are ETB triggers activated abilities?

No. When that creature enters the battlefield, both its own ETB trigger and Portcullis’s ETB trigger will go on the stack. Then each player receives priority in Active Player Nonactive player order, allowing each player to cast spells and activate abilities.

When do you get to choose the Order of triggered abilities?

This is the general rule: when the same event triggers multiple triggered abilities, the controllers of the abilities decide what order to place them on the stack, in APNAP (active player first, then non-active player) order (rule 603.3b). In your example, you get to choose.

What does triggers and Order of execution mean?

Triggers and order of execution. This means that if my before trigger did something that left the record in a non valid state, for example emptying a required field, at this point the execution will stop, because it will be re-validated. System validations validate changes performed in before trigger.

What happens when you trigger a triggered ability?

Triggered abilities don’t care whether you want them to trigger or not. If the event happens, then the ability triggers, period. Flametongue Kavu will blow itself up when its trigger resolves. Not exactly the smartest creature out there.

How to determine the controller of a delayed triggered ability?

To determine the controller of a delayed triggered ability, see rules 603.7d–f. 603.3b If multiple abilities have triggered since the last time a player received priority, each player, in APNAP order, puts triggered abilities they control on the stack in any order they choose.