When I started Aegis, I kinda just yoinked the name from Greek mythology even though the story has nothing to do with it --or even has ties to the real world or history. It was high school me just being kinda stupid and shortsighted.
kinda long lore drop warning
In the context of the story, "Aegis" is the name of the (newly established) executive division of the UR (United Realms), kinda like the UN in real life. The protagonists of the comic work for the Investigative Division of Aegis, traveling around Mylur (the world of the comic) to do detective work and solve rather large situations that go beyond borders. On top of that, they generally settle disputes and help with local forces in their own matters, building Aegis' reputation and diplomatic relations with the Realms.
On a deeper level, the organization is seen as a symbol of Mylur's societies trending towards more united, progressive ideologies. A new, young, and optimistic generation is coming up--who want to move past the discriminatory and fractured past of their forefathers. People see Aegis as representative of this new, bold world (for better or worse). But every progression has resisting forces, and our protagonists have to become a shield: Acting as a bulwark for Mylur's advancing societies; and fighting against dangerous people and ideologies that would rather destroy than see the world change.
TLDR: I chose the title "Aegis" because people think of a shield when they hear it. It is the name of a law enforcement organization. But on a thematic level, it is also representative of the moral obligation people have to defend what's right and uplift the weak.