It could mean that in this fanfiction, there is a character or situation where 'this' (whatever it is) is something that protects the Avengers. Maybe it's a new hero, a powerful object, or a special ability.
If 'this' is a superpower, it can be used directly to defend the Avengers. For instance, if it's a power of invisibility, the holder can use it to spy on the enemies and prevent surprise attacks on the Avengers.
Sure. One great 'Avengers Protect Clint' fanfiction is 'Clint's Shield'. In this story, the Avengers form a protective circle around Clint when he's in a vulnerable situation after a mission gone wrong. They use their unique powers to fend off the threats. Another one is 'Protecting Our Archer' where Natasha in particular takes on a leading role in safeguarding Clint, showing their deep bond.
In many fanfictions, the Avengers protect Hawkeye by using their unique powers. For example, Thor might use his lightning to fend off enemies approaching Hawkeye. Captain America would use his shield to block attacks aimed at Hawkeye. And Black Widow could use her combat skills and stealth to take out threats before they reach him.
One great Avengers protect Loki fanfiction is 'Loki's Redemption'. In this story, the Avengers realize Loki has been misjudged. They see that his actions were often a result of being manipulated. Thor takes the lead in protecting his brother from other threats, while Iron Man uses his tech to keep Loki safe from various Asgardian and earthly enemies. It's a really interesting take on the characters.
There's also 'Protecting Our Spider - Kid'. This fanfiction shows how the Avengers, especially Tony Stark, take on the role of Peter's protectors. They face various challenges and threats together, and the story really delves into the relationships between Peter and the Avengers. It's quite an engaging read with lots of action and emotional moments.
One common theme is family. The Avengers often become like a surrogate family for Peter, protecting him as if he were one of their own. It shows how they care for him deeply.
In a fanfiction scenario where they are facing an army of alien invaders. Hawkeye is on a rooftop providing long - range support. The Avengers form a perimeter around the building he's on. Hulk smashes any aliens that get too close to the building. Wanda uses her powers to create barriers to stop incoming projectiles aimed at Hawkeye, and Vision uses his phasing ability to pass through the aliens and take out any that are about to fire at Hawkeye.
The fanfiction can also be about redemption. Loki getting protected by the Avengers can be the start of his journey to make up for his past wrongs. It gives hope that even the 'villains' can be redeemed and find a place among the heroes, and this theme is always interesting in the world of superhero stories.
Spiderman might use his agility and web - shooting abilities. He could quickly web up Venom, restraining his movements and preventing him from attacking the Avengers.