I must say, these are not that good.
I don't mean to be mean. My first sprite was made less than four months ago and it was utterly hideous. But with the help of others, I have (hopefully) improved. So, some constructive criticism.
Sunrise Lucario. It's a neat idea in theory, or I think so anyway, but there are several problems. First and foremost is that you've shrunk the Lucario. This has made it very grainy and hard to see. Also, it is generally a bad idea to have light-colored outlines, though I guess maybe here it's acceptable due to SL's nature. The wings aren't very good either, or rather the right (our left) one: it consists of mostly straight lines, also something to avoid. The bottom feather of its right wing goes inwards, which looks bizarre. And you have six feathers in its left wing and only four in its right. Finally, you seem to have missed some of the blue when recoloring it.
Its background is rather badly done. It's just thrown together in Paint, yes? That kind of thing can offset even the best sprite. The formatting on the text looks odd too; it probably shouldn't all be in
bold italic underlines. See how odd it looks among normal text? And while it's not quite a spritework comment, my perfectionism urges me to point out that some of your grammar is awkward; it should probably go more like:
Sunrise Lucario, the most graceful of all Pokémon. It emerges from the water right at the sunrise to fly up to the sun and cast its shadow on the beach. The moment its shadow is seen, it dives back under the water to avoid being seen. To this day no-one has ever seen the Sunrise Lucario.
(I'd also like to point out that shadows are not reflected but areas where no sunlight falls.)
Thaos and Michael. Sorry, but they're just trainer sprites with bad edits that lack shading. Some of the recolored shading looks bad too, since the shades are messed up in other colors. Also, the swords don't line up, by about two pixels for the first one and the second one is hard to tell because we don't know quite what it's meant to look like.
Shadow Arceus. Well, the most noticeable thing is that it lacks shading. Its colors look odd too; the bright orange, for example, looks hideous contrasting with the purple. You've also made the outlines lighter there too, and Shadow Arceus has nothing to excuse this. You've also missed several pixels in the recoloring, again. And finally, though this isn't as important, you've cropped it to Arceus' width but not its height.
Shadow Dialga. Easily your best one, though that's not to say I have no criticism. Primarily, you've got yet more lighter outlines. The shading looks kind of bizarre, but since I think that's just a remnant of Dialga's original shading, so. The silver's outlines look very purple and that's just odd. Again you've missed several pixels in your recoloring. You've missed several pixels in your transparency, namely between its toes and between its frill-things, and one patch in between its legs. And while it's a matter of opinion, I think it'd look better if you had the purple in the space of the silver and vice-versa.
Arceatena. Well, it's rather a failure as a Fusion. All you've done is erased Giratina's wings and head and pasted Arceus' head on. What's worse is that you've
copy-flipped Arceus' head. You just don't copy-flip. The coloring would be okayish but for one thing; you've got inverted shading. The lightest shade goes on the top. You don't have the light outlines this time at lease, but you've yet again left several pixels of the old color.
...Now, so far, I've only been talking about the normal form. The shiny is just... ugh. You used the paint default colors. Never use them. You’ve also given no thought to shading, so that you've got blue with red shadows. And you have, yet again, missed some of the colors in recoloring. But this time it's worse, since it's the outline of the head. Ugh.
...*deep breath* well. That's one of the longest things I've ever typed. I hope you take it to heart and use it to improve.
(Also, your thread title seems to be inspired by mine! :3)
EDIT: Post-ninjaed about Arceatena's head and colors. Aww. Well, the rest still applies.