You can't breed legendaries in any of the games, for they are genderless. The only genderless Pokemon that can breed are more common ones, such as Magnemite, and they can only breed with Ditto. There is only one legendary that can breed, but it exists only in Diamond and Pearl thus far, called Manaphy (obtained in Pokemon ranger). If you put manaphy and ditto in daycare, you will get an egg. This Pokemon will be Phione. I'm not sure if you can breed Phione and Ditto in daycare. Note: Phione is the weaker version of manaphy.
The legendaries you can catch in Pokemon Ruby without trading or going to an event are Groundon, Rayquaza, Latios, Regice, Regirock, and Registeel.
Not legendaries but mostly all Pokemon can mate with ditto
any Pokemon except for legendaries, and a few others
A ditto can have an eg with any Pokemon but some legendaries, like deoxys, dialga, palkia, and many more. But you can breed a rotom with a ditto and make a rotom egg, and a manaphy will give you a phioni egg.
in Pokemon ruby there are these legendaries: Groudon, rayquasa, regice, regirock, regesteel, latios. (these are without cheats or events)
All The Shiney Pokemon You Can Get In Pokemon Ruby Are All The Pokemon You Can Get in Ruby Any Pokemon Can Be Shiney Even Starters and Legendaries. So There Are 200 Shiney Pokemon You Can Get In Pokemon Ruby.
Ruby Throated hummingbirds do not mate for life. The female always builds the nest and then finds a mate. Once the pair mate, the male leaves and does not help to raise or feed the young.
Pokemon ruby, sapphire, and emerald. The legendaries are groudon kyogre and rayquaza.
You can find 6 legendaries: Groudon, Latios, Regice, Regirock, Registeel and Rayquaza
No, you can't I recommend saving your game before battling rare Pokemon or legendaries.
f*** off mate
legendaries, jirachi, rayquaza, swampert, mudkip, treecko, ninjask, skitty, and loooads more"!