Hey, welcome back. :P
Yeah, shrines are by world obviously, so you can only use the shrine on your home world. You can throw as many creatu/eggs/items at the shrines as you want, and you have a chance of getting blessed items (amulets, eyes, talismans, books), and eventually when you gain enough reputation (you don't have to fill the bar, but it's usually on the higher end of it), you get a blessing, which can only be applied to creatu which have the elemental effect.
You can even get multiple blessings in a day if you have enough creatu/eggs/items and patience. :p Items have been pretty rare for me lately, so it seems like a low chance to get them, or maybe the chances drop as you do more blessings, since I used to get a lot more items.
Also the Reiflem Comet event is on right now, but should be ending soon. :o If you want to try and do anything with it, you meet Perry in Reiflem, and then go to the potion shop, and then the resurrection quest.