Tulin

Summon him and aim the gust. It pushes enemies off ledges, fills a sail, and lifts your paraglider for another second of height. Boats and rafts become much faster with him at the bow. The ability has a cooldown, shown by his avatar. If he falls off a sky island, summon him again. He is not gone, he is just not on the platform.

The arrow assist is why headshots on Gleeoks and Lynels get easier while he is summoned. You still aim near the target. The gust does the last nudge. It does not make a shot fired into the ground hit an eye in the sky. Bring him out before a boss, and put him away in a tight cave if his body is blocking a door.

Hebra is locked in a blizzard until the temple is done. You help Tulin through the quest in Rito Village, then fly up to the temple. The boss is a flying creature wrapped in ice. You paraglide in the updrafts it creates and shoot the icy cores on its underside. Tulin's gust gives you the height to line those shots up. When the cores are gone, the body breaks.

After the vow, the blizzard clears and the gust is yours on the surface. He is the first sage most people keep summoned, because travel is constant and combat gusts are a bonus. A boat from Lurelin, a fan bike that is one puff short of the next island, and a Gleeok eye are the three places you will notice him every day.