ASUS added a DIY aspect to Gladius, and as such opening it is an easy enough task. There are 4 screws hidden under each slippy pad, and when those are removed, the mouse is open. No hidden clasps, no arcane hooks, or anything of the sort.
There’s also a 0.5mm space between each slippy pad at its edge, ensuring easy detaching and positioning of the PTFE pad.
With the mouse opened I was greeted by the top ROG branded PCB with a relatively clean layout. There’s a small sticker on one of the tightened screws, on the small PCB, warning that if removed, the warranty is null. Of course that didn't stop me, especially when said ticker is so easy to remove and re-attach.
Now, ASUS Gladius uses the Avago ADNS-S3988 optical sensor, the same one used by Razer's Deathadder 4G, incidentally one of the best sensors on the market to date.
Controlling the entire set-up is a 32-BIT, 72 MHz, ARM Cortex MCU, with 32KB flash memory and 10Kbytes SRAM, which is one of the most powerful MCUs currently used by gaming mice.
The clever part of ASUS' Gladius is the swappable switch mechanic. You see, instead of right / left / scroll switches being embedded on the PCB, a socket is implemented to allow easy replacement. ASUS ROG Gladius comes with 2xOMRON D2FN-F-FN pre-installed switches rated at 20 million clicks for left & right click, and one OMRON D2FC-3M switch rated at 3-million clicks lifespan, for the scroll wheel. The package also contains 2 other D2F-01F replacement switches, these ones rated at only a 1-million click life-span.
The scroll wheel is ALPS made, and the ALPS brand was (and still is, somewhat) one of the most reputable mechanical switch manufacturers on the market. They used to make some really premium mechanical switches (they might be still be in the mech business, but they’re overshadowed by Cherry).
While the interior build is close to being perfect, it stumbles close to the finish line. The following complaint wouldn’t be a big issue on most other gaming mice, but in Gladius’ case it’s worth mentioning: On the secondary PCB, there are 3 switches which are not as reputable as the rest of the mouse is. In fact, I don't even know these blue microswitch type, I have never seen 'em in any previous mouse. They have a nice clicky feel similar to an OMRON, though less force for actuation.