Who are "Iyim", and what will they see?
Rashi: They are idolaters; they will see Hashem's mighty acts.
Rashi (8, citing Bereishis Rabah): This entire matter discusses Malki Tzedek (Shem) and Avraham. They are called Iyim - just like -islands are special in the world, Avraham and Shem were special. They saw the war. [Shem] feared lest Avraham tell him 'you established these Resha'im in the world (they are your descendants)!' Avraham feared, for he killed Bnei Eilam, who are from Shem.
Radak: They are island dwellers. They will see and hear the great matter that Hashem did.
Malbim: [All the Goyim will stand to from here Mashi'ach, even] the far islands at the end of the settled world.
Why will they come close?
Rashi: They will gather together to fight when they see the Ge'ulah.
Radak: They came in front of Avraham, like Melech Sedom, who went out to greet him. Even so, they helped each other to make idols, and did not put to their hearts how Avraham and 318 men defeated the four great kings. This was a wonder! Do not say that they were weak. They defeated the five kings, and struck the entire land 1 ! All should have realized that the G-d whom Avraham served helped him. Just the contrary, amidst their fear they increased idolatry, hoping that it would help them!
Malbim: They will gather together to fight against Mashi'ach.
On the way to fight the four kings, they defeated four nations or tribes of giants and Giborim (Bereishis 14:5-6)! (PF)