The major strength of this fruit is that it allows the user to transform into an allosaurus, a large and powerful predator from the prehistoric era, making them much better suited for combat than basic Zoans. As is the case with every other Zoan ability, the user can also become a human-animal hybrid at will.
While in full allosaurus form, Drake's own size increases, making him bigger than a Pacifista. He is also granted a strong biting ability that can even damage the Pacifistas' heavy armor, which are said to be stronger than steel. His tail is also a powerful weapon, capable of slamming people with great force. In hybrid allosaurus form, Drake becomes smaller, but still relatively large, and is capable of wielding his signature weapons for melee combat.
This fruit has no known weaknesses, aside from the standard Devil Fruit weaknesses.
In full-beast form, Drake's fighting style mainly revolves around biting. Should he capture his target in-between his maws, he will crunch and then spit them down, using Busoshoku Haki if they happen to be a Logia. He may also attempt to use his tail for surprise attacks, using his bites as a feint.
In hybrid form, Drake makes use of the immense physical boost granted by his fruit to enhance the power of his dual-wielding axe-sword combat abilities, being capable of dealing damage comparable to Monkey D. Luffy's Kong Gun to knock out even an Giant-like creature in one hit.
X Calibur (X狩場,Ekusu Karibā?, literally meaning "X Hunting Ground"): From above, Drake swings his sword to his right and his axe to his left, sriking down upon an enemy with both weapons simultaneously. The attack was first seen used against an inebriated Juki, successfully knocking out the artificialancient giant. Drake was in his allosaurus-hybrid form while performing the attack, likely enhancing its power. The attack's name is a nod to the famous sword Excalibur from Arthurian legend, with the name's kanji representing a pun: 狩場 ("hunting ground") would normally be read as kariba, matching the Japanese pronunciation of "-calibur" (カリバー,karibā?), with the preceding "X" a play on Drake's name.
As of Chapter 998, Drake's allosaurus form now features a row of spike-shaped protrusions running along its spine, a detail that was not present in its design beforehand. This is not the first time a Zoan form undergoes an artistic update in the series' run; Page One's spinosaurus form already went through two different revisions ever since its debut.
The depiction of Drake's full-beast form in his first appearance is largely based on the outdated model of the Allosaurus and other theropods that became popular in the 20th century and have since been corrected. Oda's model in particular is late 20th century.
The hands of all theropods were strong, but like birds (the theropods' modern cousins) they were usually positioned facing sideways in a "wing stance", while older media depictions positioned them more like hands. They could pin a prey animal and their arms were far stronger than those of a human's, but they could not clench to grip like Drake is shown doing.
Many depictions of Drake fully transformed have his stance too far up, with the front end raising up. In reality the stance of the allosaurus was much lower at the front, as is the case of almost all theropods.
This is the first Ancient Zoan power seen in the series, and the first to be officially named, 420 chapters after its initial appearance.