Oh Gosh, my 4e is SOOO rusty, let's see
Of course you want Wisdom to be your highest stat, followed by Con and then Int
For backgrounds, you either want Trained from birth for a Specific Prophecy, or Officer who came out of retirement
For theme, I'd pick Ghost of the Past.
For At-wills, Divine Bolts and Sun Strike are both solid.
Your level 1 encounter power should definitely be Thunder of Judgment, and your level 1 daily should be Silent Malediction
At level 2, I'd pick up Divine Call
Level 3, I would go back and grab a second level 1 encounter power: Lightning's Revelation
Level 4, bump Wis and Con
Level 5 I'd grab Searing Orb
Level 6: Demand Justice
Level 7: Rain of Blood
Level 8: bump Wis and Con again
Level 9: Cerulean Flames
Level 10: Angelic Messenger
For feats, I'd take Staff Expertise at level 1, then Mark of Storm, then Battlewise, then Superior Implement Training (accurate staff), then Improved Defenses, and finally Improved Initiative
For further reading, let me recommend the excellent guide
http://www.enworld.org/forum/showth...-the-Covenant-A-Guide-to-Invokers-(By-Cazzeo)
