| Issue | #18 |
| Published | January 2008 |
| Cover Price | 2.99 USD; 3.65 CAD |
| Pages | 36 |
| Editing | Eddie Berganza; Adam Schlagman (assistant) |
| Notes | U.S. on sale date: 2007-11-28 |
| Characters | Ion [Sodam Yat]; Superman-Prime |
| Genre | Superhero |
| Pencils | Andy Kubert (signed) |
| Inks | Andy Kubert (signed) |
| Colors | Moose Baumann (signed) |
| Notes | U.S. on sale date: 2007-11-28 |
| Characters | Green Lantern Corps [Green Lantern [Guy Gardner] (cameo); Green Lantern [John Stewart] (cameo)]; Ion [Sodam Yat; also as Green Lantern (flashback)] (origin); Guardians of the Universe; Diro Yat (first appearance; Sodam Yat's father; flashback); Cara Yat (first appearance; Sodam Yat's mother; flashback); Tessog (first appearance; flashback; death); Superman-Prime (villain); Anti-Monitor (villain) |
| Synopsis | Ion and Superman-Prime have a massive slugfest on Earth, and Ion ends up on the losing side. |
| Genre | Superhero; Science Fiction |
| Script | Peter J. Tomasi |
| Pencils | Patrick Gleason; Jamal Igle |
| Inks | Prentis Rollins; Jerry Ordway |
| Colors | Guy Major |
| Letters | Steve Wands |
| Characters | Batman |
| Script | Dan Didio |
| Pencils | Andy Kubert; ? |
| Inks | Andy Kubert; ? |
| Colors | Pete Carlsson; ? |
| Letters | typeset |
| Notes | Dan Didio discusses Countdown: Arena and breaks down 26 of the 52 Earths. Hot list - Countdown Presents: The Search for Ray Palmer: Red Rain #1, Green Lanterns #25 and Tales of the Sinestro Corps: Ion #1. House ad for Green Lantern Corps #19. |