User blog comment:BannedLagiacrus/Monster Hunter Ecological and Lore Info Blog/@comment-6050823-20150907190821

Things You May Not About Elder Dragon-Level Monsters(Info comes from Hunter's Encyclopedia, MHF-G, MH3U, MH4U, and MH2)
 * Elder Dragon-Level Monsters are monsters that can bring major damage to ecosystems or monsters that have a strength comparable to an Elder Dragon.
 * These monsters have the destructive capabilities of Elder Dragons and some even have similar abilities to Elder Dragons.
 * There are two different Elder Dragon-Level Monsters, Elder Dragon Influenced Monsters and Elder Dragon Strength Monsters.
 * Elder Dragon Strength Monsters have the strength and power to rival Elder Dragons or just are equal to an Elder Dragon.
 * Elder Dragon Influenced Monsters is a new one and has yet to be talked about.

Confirmed Elder Dragon-Level Monsters
 * Rajang: In legend, Rajang was called an Elder Dragon. Despite being a Fanged Beast, it is stated that its power is equal to that of an Elder Dragon and that Furious Rajang are truly powerful enough to take on Elder Dragons.
 * Deviljho: Deviljho's gluttonous behavior puts it on a level with Elder Dragons. It can make all nearby species in a area go extinct, including large predatory monsters. It has been seen killing and feeding on other large predatory monsters. Deviljho has also been seen attacking Rajang and Elder Dragons, not even leaving when these monsters appear.
 * Shen Gaoren: Due to Shen Gaoren constantly looking for and destroying things that disturb their territory such as towns, cities, and barriers.
 * Akantor: Akantor's overwhelming strength and the fact that it was temporarily classified as an Elder Dragon, makes it an Elder Dragon-Level Monster. It has been seen surviving in heavy thunderstorms and long droughts, before bring destruction to whole towns. When it appears, the public is evacuated from the town since it can bring on this much destruction like an Elder Dragon.
 * Ukanlos: Much like Akantor, Ukanlos was classified as an Elder Dragon, temporarily, after it was discovered. It was feared that it would eventually team up with Akantor and bring destruction to numbers of areas with Akantor. It is considered to be equal to Akantor in power and about as aggressive. Even when just being discovered carelessly or living close to a village, some Ukanlos will attack immediately without warning. This puts them at a level equal to Elder Dragons.
 * Odibatorasu: Like Akantor and Ukanlos, Odibatorasu is about equal to them. Unlike them though, it is known to prey upon not only monsters but also buildings and even rocks surrounding areas. Odibatorasu can even cause large sandstorms just with its breath. The destruction it can do by just doing this is enough to compare to it an Elder Dragon, just by destroying whole ecosystems and towns.
 * Espinas: Espinas was able to fight and defeat an Elder Dragon. Though Espinas are generally calm, this still is enough to put it with Elder Dragons. Also, the Espinas Subspecies and Espinas Rare Species are capable of this as well.
 * Unknown(Black Flying Wyvern): From the most recent Unknown(Black Flying Wyvern), it is said that it is perfectly capable of raining hell on villages and towns easily. This is enough to put it alongside Elder Dragons.
 * Raviente: Raviente is so giant that it can even go over the clouds. Although its class is unknown, it is known that it can destroy a whole island from its gluttonous behavior alone.
 * Apex Monsters: Apex Monsters exceed most Frenzied Monsters and are said to be on par with a Frenzied Deviljho. They can destroy ecosystems, infect areas with the Frenzy Virus, and even destroy settlements. This puts them as Elder Dragon-Level Monsters.
 * Apex Rajang and Apex Deviljho could actually be said to be on a level beyond some Elder Dragons.
 * Rare Species: Rare Species area about as rare as Elder Dragons and even have some abilities that is on a level with Elder Dragons. It has even been found that some Rare Species use the Dragon Element like Elder Dragons, though isn't really noticeable most of the time.