Removing the side panels is easily achieved by loosening the pair of thumb screws holding each side in place. The perforated one feels very fragile, so you have to be really careful not to end up bending it. Azza may have to use a thicker metal sheet to add some rigidity to this kind of side panel. The interior of the Legionaire is quite traditional, and Azza isn't making any attempts to go beyond the OEM baseline for the most part. This includes the shroud, which offers up the possibility to install two 120 mm intake fans here. Even when doing so, you should have enough room to route and attach cables to the bottom edge of the motherboard. Unfortunately, none of the openings within the Legionaire come with any grommets and even though there is the possibility to mount, it also does not include a GPU support bracket as a value-add for example. In the rear, things look quite traditional as well, but the case only offers a single row of hooks for zip ties along the front of the case and some on the fold around the CPU cooler cutout. In other words, the case could really use more of them for best possible cable management. Speaking of which, there is a surprising amount of wiring here considering what the chassis ships with.
On the back of the motherboard tray, you will find two individual 2.5" trays, which may be removed easily during the assembly process. To the left of those, there are two rows of square cable routing opening which really could use those grommets. On the upside, even E-ATX board users will still have the same level of cable management possibilities as those employing ATX variants, which is nice to see.
In the front, underneath the shroud, you will find a metal hard drive cage with a single tray. It may also hold an additional drive on top, but to install that, you will have to tip the chassis over and remove four screws to remove that cage in the first place. Above that are the three 120 mm intake fans. In fact, Azza lists all four of these as LFO-3812D models, but doesn't sell these separately. As such, these cannot be considered retail and there is a good reason due to the wiring used, as we will see in a little bit.
In the rear, the PSU bay comes equipped with foam strips as an anti-vibration measure. While Azza does not communicate how big of a unit will fit without any compromises, considering that the Legionaire is a little bit deeper than other mid-towers, you should be fine for all but the longest units out there. Above that are the seven expansion slots, with a slidable cover to close the gap to the side of them. In the very top there is that fourth LFO-3812D fan, which is a bit different than the rest as it utilizes a PWM connector on top of all the other wiring.
In the ceiling, you can see that there is plenty of room for a classic AIO to fit without getting in the way of the motherboard, which is nice as you won't have to worry about large boards or tall memory. That said, it will make connecting the cables along the top of the motherboard a bit harder, but not impossible.
Now, about that cable mess previously mentioned: it is due to the unique, proprietary wiring of the fans. Starting with the rear, which sports a classic ARGB plug for motherboard control as well as a PWM connector sorely for receiving the motherboards signal to pass on to the other three fans though their proprietary connectivity. A SATA cable provides power to all of them. The tricky aspect relates to the fact that the Azza logo in the front is also ARGB. As such, it also comes with the exact same proprietary connector the fans use. However, you may not daisy chain that with the fans or your ARGB won't work properly. Instead you have to plug that one into the identical connector from the SATA wiring. Sounds confusing because it is. That said, the digital manual does provide a diagram of this, but Azza should have at the very least added labels to the wiring in case you do not have access to a phone or the internet when building the system.
In short, the Azza Legionaire utilizes proprietary connectors on two levels - on one hand, there is that special "control" fan in the rear with its unique plugs & then there are the ones in the front that interface to that unique connections to get PWM & ARGB data passed. On top of that, the added cable mess doesn't help.
There is absolutely no excuse for this type of wiring to be used at all and Azza should instead stay miles away from this. Besides that, the wiring and plugs for the IO is of default variety with black sleeving.