Cosmic Custodian

The Cosmic Custodians are several character created for public domain by Micheal P. (who is also called "Yzz"). He also created two alternate realities for these characters to live in. Earth-A was actually fleshed out unlike Earth-I. Both settings are also public domain.
Earth-A

The two versions that Micheal P. created

This version is extremely similar to Green Lantern. The Cosmic Custodians are an intergalatic police force. The powers band are created by the unseen characters called "Keepers of the Cosmos".
The first Earth Cosmic Custodian was pre-World War I Irish-immigrant Jeremy O'Brien, who worked as a farmhand. He got the power band from a miniature star that turned into the bands when he volunteered to become a titan (superhero). He started his carrier in 1914 thus becoming the second titan. He helped stop World War One and accidentally prevent the rise of the Nazis in Germany. Despite this, World War II (called the "Second Great War") still happened for some reason. He died in the war. Four unseen people also became the Cosmic Custodian at one point or another. The current Cosmic Custodian (the sixth) is David O'Brien, Jeremy's descendant. David has glowing blue eyes.
The Cosmic Custodians use power bands. The power bands gives the use life support, energy projection, flight and super durability. David (unlike the rest of the Custodians) can make simple energy constructs.
Earth-I

The robot version

This version is an alien robot. The aliens created the machine to protect the solar system (which they saw as their property). The Custodian laid dormant for thousands (if not millions) of years. What happened to these aliens in not explained. The CC was turned on by alien raiders. He decided to stop any alien invasion, but is unsure what to do with the "aliens" already in the solar system.
This version had a different set powers than his Earth-A counterparts. He has high-level invulnerability and super strength. He is super smart. CC can fly faster than light.
Citations
Micheal P. wants people to credit him for his creations. However, I found two different citations. For the Earth-A version, you have to insert:

"Earth-A, Athena (Earth-A) , Cosmic Custodian, and Scarlet Stalker (Earth-A) were created by Michael P. and are available for use by anyone, with only one condition: This paragraph must be included in any publication involving Earth-A, Athena, Cosmic Custodian, and Scarlet Stalker, in order that others may use these properties as they wish. All rights reversed."

However, the Earth-I has a different citation:

"Cosmic Custodian was created by Michael P. and is available for use by anyone, with only one condition: This paragraph must be included in any publication involving Cosmic Custodian in order that others may use this property as they wish. All rights reversed."

References:
http://pdsh.wikia.com/wiki/Cosmic_Custodian_(Earth-A)
http://pdsh.wikia.com/wiki/Cosmic_Custodian_(Earth-i)