The kobold racial trait Grovel, Cower, and Beg is described as follows (VGtM, p. 119):
As an action on your turn, you can cower pathetically to distract nearby foes. Until the end of your next turn, your allies gain advantage on attack rolls against enemies within 10 feet of you that can see you. Once you use this trait, you can’t use it again until you finish a short or long rest.
When does Grovel, Cower, and Beg take effect? That is, when is the 10-foot range checked for determining whether allies have advantage against an enemy?
Suppose a kobold starts 5 feet away from an enemy and uses an action to Grovel, Cower, and Beg, then spends all of his movement to run away. He finishes his turn 35 feet from the enemy. The kobold's ally is next in the turn order.
I can interpret the ability's effect in two ways:
- The kobold's ally gains advantage when attacking the enemy because the kobold was within 10 feet of the enemy at the time the ability was used.
- The kobold's ally does not gain advantage when attacking the enemy because the kobold is more than 10 feet away from the enemy at the time of the attack.
On a side note, I found plenty of other questions about kobolds and their abilities (e.g. Pack Tactics), but I haven't been able to find a single question about this ability on RPG.SE.
Best Answer
The Ability is Continuous
Grovel, Cower, and Beg takes an Action to activate. The effect is checked every time an ally makes an attack.
If the foe is a) within 10' of the kobold and b) can see the kobold (not blocked by cover, darkness, blindness, invisibility, etc.) and c) the duration for GCB hasn't expired then the attack has Advantage.
If your scenario, the ally would not get Advantage because the target of the attack is 35' away from the kobold.