who would win also how did cap atom become the monarch .

Poor editorial decisions and being unfortunate enough to be a Charlton character instead of a DC original.

I miss you Blue Beetle. I miss you.

i never seen the big deal about blue beetle he came off as a poor mans bat man to me .

To each his own.

But man, those Steve Ditko stories were amazing. Ah the Silver Age.... if I had a time machine I'd propel Gil Kane, Ditko & Gardner Fox into this decade and keep Dan Didio's and Joe Q's parents from ever meeting.

Long story short, Captain Atom went up in a oddly shaped rocket to try to deflect an asteroid. He was then shunted off to the Wildstorm universe. He saw how different attitudes were there, like killing bad guys was no big deal.
Anyways, after he left there, he landed in Bludhaven at a bad time. And he was leaking radiation. The Atomic Knights found him, and after sealing him up in a suit, he was Monarch.
He left Budhaven and was later seen by Ion in the Bleed. He helped Ion and two kids get out of there and back to the DC universe they all knew and loved. (Ion was shunted to the Bleed by the Tangent GL)

Originally, Captain Atom was suppose to be the original Monarch, but, that was changed and they made Hawk (of Hawk and Dove fame) become Monarch. Then he became Extant, I believe. It's been awhile since I read those stories.

oo ok thanks mr jtr i still dont see why he is so powerfully now .

At this point we don't know.
I have a theory though.
At the end of the extremely excellent and awesome Captain Atom series Cap doesn't appear at all Monarch like.
BUT during the incredibly poorly named book Extreme Justice days He met up with a future version of himself who had taken on the Monarch name and suit.
I think that the Captain Atom we saw in the last ish of Arena was the New Earth Cap, and this guy is that long forgotten bad-guy!

But the bottom line is even in interviews writers haven't said mum, nobody knows how Monarch became what he is or really what version of Captain Atom he is.

I happened to think that Arena was wicked fun, and getting to see the original Captain Atom again was great.