I'm rewatching OOO and I somehow didn't notice this! This is awesome!!

Well dang that's an impressive detail to add! Really emphasises OOO's animal motif.

Kudos to your eagle eye for catching that.

No, no, silly -- the eagle having super eyesight is Zyuohger; in OOO it's the hawk that has super eyesight :p

It gets really obvious when you see the random combos consecutively.

https://youtu.be/HQxX3Wz19Eg?t=506

While listening to Over Again, I realized that, at the time, W, OOO, and Zero-one's music are all callbacks to the original Kamen Rider's use of trumpets.

Kamen Rider V3 started with a jaguar-type kaijin in the form of Hasami Jaguar. Agito also started with a jaguar-type in the form of the Jaguar Lords. I am gonna say it is probably an intended tribute to V3 as much as G3 is a tribute to Riderman. Both are the second season of their respective eras so I guess it makes sense they do something like that.

Oh cool, in the same way that Kuuga (and many others after) had a spider as their first monster to homage Ichigo's first monster!

And, if you wanna stretch this a bit, Gills heavy ties to water also can be tied X with his underwater motive. Would all make sense since Inoue's dad worked on Showa Rider as far as I remember and that Inoue likes referencing it.

I like to think Gills got his name based on Inoue's' love of having scenes where people are floating on or otherwise in water. Seriously, there are a ton of those throughout Agito and Faiz.

Now that you mention it, Keisuke also loses a lot of people he cares about, including both his dad and girlfriend (one of my favorite silly bits of X is when Keisuke’s dad leaves behind a submarine base and computer based on his personality, which immediately destroys itself the second Keisuke shows any sign of emotional attachment).