Imagine: You're a Takish fighter pilot, flying a routine nightly patrol mission, when briefly, out of the corner of your eye, you see something fly through the air, at speeds no aircraft could handle, let alone reach. You look down at your radar in panic, hoping that it has any trace of whatever that was, but nothing... And the next moment, your RWR flashes, and you desperately pull for an evasive maneuver, but it's no use...

This would be the average encounter against the legendary hypothetical Lasa fighter, Borealis (Or as the documents call it: B-C.L.A.S.S.).

Information: The Borealis was a supposed 7th generation super fighter, which could hit over one hundred G's, and a solid Mach 3 flight duration of days, at least. It would've achieved this by using a completely new type of engine, which used a fission-fusion cycle system (basically the engine would have tons of helium gas in it, which would first be broken down into hydrogen, and fuse back into helium, and somewhere in the process, some of the energy would be released, propelling the aircraft forward).
It would have also had extraOrdinary stealth capabilities, appearing practically invisible to both radar, and even the naked eye, by using some type of light warping invisibility coating, or small scales on the skin that would shift to warp light around it. And it's offensive armament was no joke either, as it would've had a pair of constant fire tactical laser systems along with a pair of plasma cannons, and mainly B-Class missile (not much is known about the weapons, as we have very few images of it) radar guided missiles for the ranged armament... And keep in mind... This was all in the 60's, and 70's in the earliest

"Too good to be true" you might be thinking to yourself, and that's because it probably is, as this was only a rumored fighter, with no definitive proof of its existence, even with the "recorded" 200+ air to air kills it has...

But let's revert to the start, in 1961, were 3 Takish TV-36As suffered "spontaneous" major engine failure, and exploded midair. While most people just though it was faulty factory works, some people (mostly ex-pilots and DWW2 veterans) came up with their own explanations, mainly because the engine exploded too fast, as apparently, it exploded from the top (don't take that out of context :3), which is unusual as the fuel ports for the TV-36's engine are on the sides. This was less a direct confirmation of Borealis, but more so a weird shot in the dark.

The second instance was in 1972, when a bunch of secret documents, allegedly stolen from the Devaron Experimental Airbase, was published on a news channel. They showed the 50th page, more so transcript with Joan Ejjan (head of the RLAF at the time) and Sayene Elven (the Lass prime minister at the time). The transcript shown wrote:

[Ejjan]: Has the request been sent?

[Elven]: Which one, many have been sent from all different bases.

[Ejjan]: The one for the two **B-Class** aircraft

[Elven]: Yes, it has. It will probably be completed soon.

The B-Class aircraft probably referred to the S.A.V.A. B, but the order being in such a low quantity, for such a cheap aircraft has raised a bunch of questions.

But the most significant, and definitive proof for the existence of Borealis, is this:

This was taken in 1974, by a small camera on an M-26. This could have been only one thing if not the Borealis, the M-36 forward swept wing prototype, but the wing shaping matches a lot of other descriptions given by Takish pilots, so it probably is the fabled Borealis...