TF's Big Cat Hybrids
Hybrids are rather uncommon, other than crossing between subspecies of Ketio(Great Lion), or crossings between Ketio and Eit-Ketio(uncommon, but not rare by any means). I'm going to go over a few different types of hybrids actually seen in the series, and some that are just potential mixes, but don't actually happen.
Eit-Ketio x Ketep ("Leopard")
These crossings can't really be called "Leopons"(leopard father, lion mother) and "Lipards"(lion father, leopard mother), because the Ketep aren't leopards, but rather a strange lion-like species, that just happen to look like overgrown leopards. Still, I do refer to the offspring of the Eit-Ketio and a Ketep "Leopons" and "Lipards", for the sake of simplicity and the fact that people would recognize the names more likely. This type of hybrid is quite rare, due to most Ketep having a deep hatred for both the Ketio and the Eit-Ketio, but more so for the former than the latter. However, physically, it is quite possible, as Ketep females are rather close in size to the Eit-Ketio lionesses, and male Ketep are about as big as the smaller end of the male Eit-Ketio range.
In the Terra Fera series, only one such crossing is ever seen, in the forbidden love between an Eit-Ketio male named Callum, and a Ketep female named Frosted Glade. Frost was raised not to hate lions, having an adopted brother who was a Southern Ketio(who ends up dwarfing her when they're grown up XD). Callum was raised by Ketio parents, his birth mother having been killed protecting him from a male Eit-Ketio, and his adopted family arriving just in time to snatch him from the jaws of death. So neither of them had a normal up bringing for their species. The two at some point met, fell in love, and eventually had cubs. They only have one litter in which two cubs were born, a male and a female.
As far as size goes, Mar-Berkona and Arlan slightly outweigh both their parents, which is possibly due to some distant Ketio ancestry on Callum's side(he comes from some Coastal Capareon Lion ancestry). Ketio genes have a way of being persistent, yet remain dormant, so Callum himself having mostly Eit-Ketio genes, which are from African ancestry, lacked the ability to "trigger" those dormant genes. Frost, however, being a Ketep which is a very close cousin to the Ketio, would have the ability in her genetic code to activate those dormant genes. (I'll talk about this more with Ketio hybrids.)
In most cases of a pure Eit-Ketio and a pure Ketep crossing, size would probably be closer to the Ketep than the Eit-Ketio.
In history of TF's big cats, hybrids between Ketep and Eit-Ketio may have actually happened a little more regularly in the past. There was a time when the Ketep held no hatred for their feline brethren, and so a paring between an Eit-Ketio and a Ketep would not have been seen as a taboo, as it is in Callum and Frost's time. In fact, Eit-Ketio mixing with Ketep, may be the reason Ketep are not as massive as their Ketio cousins.
Ketio x Eit-Ketio
This crossing is fairly common in the southernmost regions of Lossuri, where the Eit-Ketio outnumber the Ketio. Generally, Ketio look down on such a pairing, as they truly believe they are far above the Eit-Ketio, who they call savages and barbarians. Although the Eit-Ketio have evolved an intelligence level high enough to call them a Kei race, they have not lost the savagery and brutality of their African ancestors, especially when it comes to the males. Male Eit-Ketio rule prides the same way African males do, and they take over them the same way as well... The Ketio, who believe killing the cub/young of any Kei race is sin against Utura(or Nature) and truly the wrong crime, do not take kindly to cub killers, and usually refuse to even speak with Eit-Ketio. However, a Ketio male, or even a group of them, will gladly take over an Eit-Ketio pride(the Ketio way, I might add), and no Eit-Ketio male would ever stand a chance against them. These cross species prides are often far more successful than purely Eit-Ketio prides, due to the brute strength of the Ketio males, and the coordination and cooperative hunting of the Eit-Ketio lionesses. (Ketio lions don't usually hunt cooperatively, but do share kills.)
A cub from this type of pairing will likely end up mostly as a smaller version of the Ketio parent, due to how heavily dominant Ketio genetics are. However, there are fatal births too, in cases of the cub getting the Ketio parent's toxic blood without getting the immunity Ketio cubs are born with to the toxins. This will cause the cub to die soon after birth(meaning it had some resistance to the toxins), or not at all(meaning it had no resistance). This is more common in Ketio mothers where the father was an Eit-Ketio, due to the mother's own system basically killing the cub. However, this means only the strongest cubs will survive.
It should be noted that an "lipard" or "leopon" that I talked about first here, and a Ketio crossing, would likely not result in the fatal mixture, because Ketep have a natural immunity to the Ketio toxins. Same would go for a crossing between an Eit-Ketio/Ketio hybrid and a pure Ketio, as the hybrid would have the genetic resistance of their Ketio parent.
These hybrids are prone to the usual cause of death for the Ketio, which is the "wear and tear of war", but it kills them even quicker due to the weakened resistance of Ketio toxins, despite the fact that the toxins themselves are weaker than a pure Ketio's blood. Even this weakened amount of the deadly concoction is fatal to most things.
Eit-Ketio x Ketep ("Leopard")
These crossings can't really be called "Leopons"(leopard father, lion mother) and "Lipards"(lion father, leopard mother), because the Ketep aren't leopards, but rather a strange lion-like species, that just happen to look like overgrown leopards. Still, I do refer to the offspring of the Eit-Ketio and a Ketep "Leopons" and "Lipards", for the sake of simplicity and the fact that people would recognize the names more likely. This type of hybrid is quite rare, due to most Ketep having a deep hatred for both the Ketio and the Eit-Ketio, but more so for the former than the latter. However, physically, it is quite possible, as Ketep females are rather close in size to the Eit-Ketio lionesses, and male Ketep are about as big as the smaller end of the male Eit-Ketio range.
In the Terra Fera series, only one such crossing is ever seen, in the forbidden love between an Eit-Ketio male named Callum, and a Ketep female named Frosted Glade. Frost was raised not to hate lions, having an adopted brother who was a Southern Ketio(who ends up dwarfing her when they're grown up XD). Callum was raised by Ketio parents, his birth mother having been killed protecting him from a male Eit-Ketio, and his adopted family arriving just in time to snatch him from the jaws of death. So neither of them had a normal up bringing for their species. The two at some point met, fell in love, and eventually had cubs. They only have one litter in which two cubs were born, a male and a female.
As far as size goes, Mar-Berkona and Arlan slightly outweigh both their parents, which is possibly due to some distant Ketio ancestry on Callum's side(he comes from some Coastal Capareon Lion ancestry). Ketio genes have a way of being persistent, yet remain dormant, so Callum himself having mostly Eit-Ketio genes, which are from African ancestry, lacked the ability to "trigger" those dormant genes. Frost, however, being a Ketep which is a very close cousin to the Ketio, would have the ability in her genetic code to activate those dormant genes. (I'll talk about this more with Ketio hybrids.)
In most cases of a pure Eit-Ketio and a pure Ketep crossing, size would probably be closer to the Ketep than the Eit-Ketio.
In history of TF's big cats, hybrids between Ketep and Eit-Ketio may have actually happened a little more regularly in the past. There was a time when the Ketep held no hatred for their feline brethren, and so a paring between an Eit-Ketio and a Ketep would not have been seen as a taboo, as it is in Callum and Frost's time. In fact, Eit-Ketio mixing with Ketep, may be the reason Ketep are not as massive as their Ketio cousins.
Ketio x Eit-Ketio
This crossing is fairly common in the southernmost regions of Lossuri, where the Eit-Ketio outnumber the Ketio. Generally, Ketio look down on such a pairing, as they truly believe they are far above the Eit-Ketio, who they call savages and barbarians. Although the Eit-Ketio have evolved an intelligence level high enough to call them a Kei race, they have not lost the savagery and brutality of their African ancestors, especially when it comes to the males. Male Eit-Ketio rule prides the same way African males do, and they take over them the same way as well... The Ketio, who believe killing the cub/young of any Kei race is sin against Utura(or Nature) and truly the wrong crime, do not take kindly to cub killers, and usually refuse to even speak with Eit-Ketio. However, a Ketio male, or even a group of them, will gladly take over an Eit-Ketio pride(the Ketio way, I might add), and no Eit-Ketio male would ever stand a chance against them. These cross species prides are often far more successful than purely Eit-Ketio prides, due to the brute strength of the Ketio males, and the coordination and cooperative hunting of the Eit-Ketio lionesses. (Ketio lions don't usually hunt cooperatively, but do share kills.)
A cub from this type of pairing will likely end up mostly as a smaller version of the Ketio parent, due to how heavily dominant Ketio genetics are. However, there are fatal births too, in cases of the cub getting the Ketio parent's toxic blood without getting the immunity Ketio cubs are born with to the toxins. This will cause the cub to die soon after birth(meaning it had some resistance to the toxins), or not at all(meaning it had no resistance). This is more common in Ketio mothers where the father was an Eit-Ketio, due to the mother's own system basically killing the cub. However, this means only the strongest cubs will survive.
It should be noted that an "lipard" or "leopon" that I talked about first here, and a Ketio crossing, would likely not result in the fatal mixture, because Ketep have a natural immunity to the Ketio toxins. Same would go for a crossing between an Eit-Ketio/Ketio hybrid and a pure Ketio, as the hybrid would have the genetic resistance of their Ketio parent.
These hybrids are prone to the usual cause of death for the Ketio, which is the "wear and tear of war", but it kills them even quicker due to the weakened resistance of Ketio toxins, despite the fact that the toxins themselves are weaker than a pure Ketio's blood. Even this weakened amount of the deadly concoction is fatal to most things.