Ok look before I really get into writing this, I must say, I am a green player, and I really and truly enjoy the interactions green has with white and sometimes black and blue, where it permanently pumps creatures. It feels like a much more green way of affecting creatures, survival of the fittest and all. I should also say, I am predominantly a Limited and a casual/multiplier person; so all opinions I'm about to voice have little baring on Standard, Modern, or any other competitive formats save for, the fact that the card I'm about to talk about is good.
Of course I could be completely blind siding you because, lets face it, I host one of the only magic flavor focused podcasts on MTGcast. Now we have seen Ajani four separate times and he has a clear character arc between those different cards. We were first introduced to the first White aligned planeswalker in the card Ajani Goldmane. He was one of the original five who were intended to appear in Future Sight, but were instead printed in Lorwyn.
Unlike the other planeswalkers, this Ajani was a more developed character from the beginning. His missing eye and pure white fur immediately show that he doesn't even fit in with the leonin who we had seen in magic before him. On top of that he is still one of a very short list of non-human planeswalkers, and of an even shorter list who could not pass off as human. For those who are confused here, the only other non-human planeswalkers are Karn, Xenagos, Kiora, Nicol Bolas, and if you chose to count them Nissa and Sorin. However most of the true story behind so many people's favorite Cat man of order, hope, and light wasn't explained or even given any flesh until Alara Block.
You see the card Ajani Goldmane is actually an older wizened version of Ajani, who had already survived the actions in Alara Block. The Ajani we first met had taken years to calm himself and embrace white mana more completely, using a combination of healing, summoning and the empowerment of others, where as his younger self we met in Alara was a red and white planeswalker whose spark had just ignited and who had just had his world figuratively and literally shattered.
You see, Ajani was born on the fractured plane shard of Naya, a shard whose primary color was green but also embodied red and white mana. He was the younger brother to the chief of his tribe and already a fairly skilled White mage. For some reason the humans of Naya began to hunt him. His brother sought to discover why, but to no avail until another attack came against their tribe, this one empowered by the black magic of Grixis sending abominable horrors into the sleeping camp of the Leonin. Ajani awoke in the fighting and tried to save his brother, but before he could reach his kin Ajani watched his brother breath his last, and Ajani's latent spark ignited and he accidentally jumped to shard of Jund. This is where we got Ajani Vengant, a red white cat man who began walking between the different shard of Alara in an attempt to discover why his brother had been murdered. Unlike all other times we see ajani represented through his life this is one time where his abilities are based on him being able to deal damage and fight back, where as his other forms focus on healing magic and increasing the power of others.
As Ajani Vengant explored the other shards and learned other ways of life he began to temper his anger until he reached the climax of his search. He discovered that the Elder Dragon, and only remaining Pre-mending planeswalker, Nicol Bolas was artificially accelerating the Conflux, a spell that would untied the five shards of alara into one whole plane once again. Bolas wished to use the magical energies the Conflux would release to regain the godlike powers he once held before the mending. Ajani fought with the dragon and, albeit in a minorly cheaty way, is still the only being to have taken the dragon in single combat. The Battle was going poorly of Ajani, until he began to fall back onto the white aligned magic he was more skilled in. He summoned an avatar of the Dragon's soul and the two were so evenly matched Bolas was forced to flee before he could gain the power he sought from the Conflux. After Alara Ajani Vengant would become the Ajani Goldmane we first met before his interactions with the rest of the Multiverse would alter him further, but we get to that next time.