Since
@Shadowslash125 is supposed to give verdict after several hours, I will summarise all my counter arguments against Groudon sups.
1. Groudon will kill Roaring Knight before it crosses 4 km distance.
Knight has FTL movement speed, crossing 4 km distance obviously wouldn't take too much time. At best Groudon would get 1-2 free actions before facing Knight swords
2. Beams and Precipice Blades would tag Knight.
Groudon did tag other flying enemies with it. But Knight is more mobile than flying opponents Groudon faced, has shapeshifting and teleportation, and is much smaller than Kyogre or Rayquaza. I should repeat this: size differences are very important in this fight. It would be very hard to hit Knight, while Groudon himself is big easy target for swords. Also, Precipice blades seems to detonate some time after their summoning, which gives Knight enough time to run from them.
3. Groudon won't allow Knight to summon Titans vua earthquake, and would easily kill them.
Groudon wouldn't use earthquake (ground move, duh) against Knight, before she starts summoning Titans. Earthquake would be able to prevent formation of new Titans(for as long as ability works), but it won't be able to kill summoned Titans, since they are very big creatures with mid-high regen, and earthquake would target only minor parts of their bodies. Some of Groudon abilities would kill them, but he would need to target individual Titans. And any moment Groudon uses these moves, is moment it doesn't use earthquake, which allows Knight to summon even more of them. Desolate Land would probably allow Groudon to passively melt Titan shields(via harsh sunlight), but Titan body and wings don't have weakness to light. Also, time spend to destroy Titans is time given to Knight to freely came close to Groudon without need for dodging dangerous attacks. I can safely assume that Groudon would prioritise giant Titans over small Knight, isn't? (Additional question: does Groudon have resistance to fearhax? Cus if he doesn't he would get negged by any close Titan or Titanspawn).
4. Groudon can sense Knight presence, since many normal pokemons can do it.
Only example sups provide are for pokemons feeling presence of electric Pokemon,
Zapdos.
I wager even I would easily be able to feel presence of the strong electric pokemon. Won't exactly help here.
5. Groudon passive heat would melt all Titan and Knight swords.
Sups didn't answer my question on "how high passive heat of Groudon is in the start". Scan they provide did say that he can increase temperature enough to kill all pokemons and humans, but I heavily doubts it's something that it can use right from the start. Extreme harsh sunlight can vaporise water easily from the moment it casted, but it's not enough to actually melt Titans.
And even if he had aura of 10225K passive heat around itself, it wouldn't be able to shield Groudon from swords. "It's higher than steel melting point, it should be able to instantly melt it before they reach Groudon", not how it works in thermodynamic, buddy.
For melting something you need high rate of thermal energy transfer + sufficient time. There are numerous instances of humans surviving 28,000K lightning, due to the fact that their bodies experience such temperatures only for brief moment, usually milliseconds. Melting point for most metals is only several thousands K, but average temperature for plasma arc cutters is around 28,000K to ensure that metals would be cut in reasonable time(if you want to cut metals as fast as lightsabers, you would need much higher temperatures, up to 54,000K).
Groudon passive heat wouldn't be able to melt Knight swords(which have FTL speed, you know). It's just not enough time for them to work.
6. Groudon can dodge via evasive moves
These moves require significant time for setup. And they wouldn't be that useful against danmaku like
this. You dodged first sword via jumping, good, now dodge second sword while in the air (also, address circle of doom that would envelop Groudon from each side). Groudon is just too big of target to successfully dodge hard and fast danmaku of Knight. And if all else fails, Knight just triggers final attack, lift Groudon from the ground, and deals with it via duraneg bullets or spatial cut.
I think I did respond to main arguments for Groudon. If there is anything left, that I didn't address, tell me about it.