score:3
The Pali scriptures say:
Mendicants, there are five destinations. What five? Hell, the animal realm, the ghost realm, humanity and the gods. Nirayo, tiracchānayoni, pettivisayo, manussā, devā—
And what is the diversity in kamma? There is kamma to be experienced in hell, kamma to be experienced in the realm of common animals, kamma to be experienced in the realm of the hungry shades, kamma to be experienced in the human world, kamma to be experienced in the world of the devas. This is called the diversity in kamma.
Other examples of the above ordering are here.
Therefore, the ordering of the five realms in descending order is:
However, it appears one sutta, from thousands, namely, Iti 93, includes a separate asura realm and places asura below hungry ghosts.
Being unaware of these three fires, humankind (pajā = people) delights in personal existence.
Unfree from the bonds of Māra They swell the ranks of hell, existence in the animal realm, asura-demons and the sphere of ghosts.
Iti 93
Therefore, based on Iti 93, the descending order is:
Upvote:2
I suspect that both the ones you quoted are correct -- the thing is that, you're assuming that "titan" and "demi-god" are the same, but I don't think they are -- according to this reference to The Thirty-one Planes of Existence, a "demi-god" is presumable a Deva (above human) whereas a "titan" is presumably an Asura (below human).
As for the ordering of Animal versus Ghost, this reference agrees with Dhammadhatu's answer (based on Pali scriptures). The Wikipedia article you cited explains its reasoning (i.e. that the contrary ordering has an origin in the Tibetan tradition):
According to McClelland, this realm is the mildest of the three evil realms. According to Yangsi Rinpoche, in contrast, the suffering of the beings born in the realm of the hungry ghosts is far more intense than those born in the animal realm.
Even then I'm not sure what criteria people use to order them -- for example "hungry ghost" might be closer to (more similar to and more akin to, more closely related to) human than the animal realm is, therefore higher in that sense -- even if the suffering of that state is greater, therefore lower in that sense.