Fireheart x Tigerclaw
FireTiger / TigerFire
Tigerclaw and Fireheart are mortal enemies, so Enemyshipping can be safely classified as crack pairing, with little or no evidence to support it. However, a philosopher once said that the emotion of hatred is much like that of love. It seems that any main character can't escape being shipped with another, and even mortal enemies are no exception to this.
Since it's obviously not about undying devotion, what is Tiger x Fire about? That's a good question with a few ansers. Since this ship is so unusual, the fan base has not reached a quality consensus on it. When not given a crack spin, FireTiger can be an angsty story about ambition and admiration between two cats who cling to a facade.
THEORIES AND FAN VIEW
Tiger x Fire is more of a fan novelty then a popular shipping. One point made in Stella's fanfiction Back Again is that without Tigerclaw, Firestar would never have been made leader, and in extension, never even been invited to the Clan.
"EVIDENCE" AND "SUB-TEXT"
There is very, very little of anything that could be seriously considered canon subtext. The only thing that keeps this pairing in non-canon instead of crack is the idea of love-hate and enemy shipping.
"Firepaw looked up at Tigerclaw, admiring the strength that swelled in his powerful muscles and broad head."
Into The Wild, page 45
So it's a bit early for this kind of thing - but Firepaw does admire Tigerclaw's physique in this sentence. Admiration canonnly for strength that Fireheart looks up to, but shippers might see if differently.
"Tigerstar was panting now, his fight for life exhausting him. Firestar caught a glimpse of his amber eyes, glazed with pain and fear and hatred. Then his body gave one last jerk and lay still."
The Darkest Hour, page 234
Interesting that in Tigerstar's dying moments Firestar is searching his eyes for emotion, no?
"Frozen in disbelief, Firestar stared down at the lifeless body. His oldest enemy, the most dangerous cat in the forest, the cat he had expected to fight to the death - gone, just like that."
The Darkest Hour, page 234
Since Firestar speaks in the same sentence that he had expected to be the one to kill Tigerclaw himself, what would normally be considered a weak subtext means less then it would. However, note the amount of shock and remorse(?) in Firestar's thoughts in this paragraph.
"But Firestar had always expected that he would be the cat to strike down, risking his own life in combat with the massive warrior. Instead, now that Tigerstar lay at his paws, staining them with blood, he found himself struggling with strangest feeling of all - grief."
The Darkest Hour, page 236
Hold the phone for a second - Firestar is staring at Tigerstar's body while he allows his paws to be stained with said dead warrior's blood? Well really, this is discredited again by Firestar talking about killing Tigerstar, and his thoughts of grief being 'strange', but, it's still there.