Hi there! Answers/spoilers can be found under the read more! :)
Also, just for future reference, I’d recommend looking through my arslan senki spoilers tag, or bowie reading arslan senki tag for more information about the novels and for answers to questions someone else might have already asked. :D (I really need to organize those tags though, damn.)
So, for those who don’t know, Ruknabad is the enchanted sword “forged by the shards of the sun” that Hero King Kai Khosrow used to fight against the Serpent King Zahk and bound him inside Mt. Damavand for centuries.
Arslan does, in fact, obtain Ruknabad, but I gotta go re-read some bits to remember what happened, haha. Hirmiz, under the sorcerer’s influence (claiming that since Hirmiz is the rightful king of Pars, being able to wield Ruknabad is a symbolic significance for his stature), goes and retrieves the sword, only to be interrupted by Gieve. Once Hirmiz removes the sword from Khosrow’s casket, however, there’s a huge earthquake immediately, and Xandes, panicking about the fact that Zahk is coming back, throws the sword into the depth of a crack on the ground caused by the earthquake.
The sword doesn’t get mentioned much again until book 7, when Arslan, determined to become Shah and knowing that Ruknabad is a significant symbol of Pars’ ruler, decides to journey to Mt. Damavand to retrieve it himself. The group is forced to take shelter when a rainstorm suddenly hits, but Arslan knows that he must use his own powers to summon the sword into his possession, and so with a genuine prayer/implore/promise to the spirit of Kai Khosrow that he’ll implement fair policies within the country and be a good ruler, the earth shakes beneath his feet and opens up in a flood of bright light. When the light subsides, Ruknabad is in Arslan’s hands.
What happened to Andragoras?
Short answer: he died at the end of the first arc.
Long answer from where the anime currently left off: he manages to escape from prison, takes Guiscard as hostage, and finally escapes from Ecbatana with Tahamine to Peshawar, where he then proceeds to keep acting like a jerk and kick Arslan out of the citadel despite how much work his son has done and ignoring how many of Arslan’s followers sincerely supports him.
What happened to Hirmiz?
WELL. A LOT of shit happened, actually, since he’s still around in the second arc of the story. Basically at the big show-down in Ecbatana between him and Andragoras at the end of book 7, he finally knows his own origins: he’s not actually Osroes’ son, but Gotarzes’ (Andragoras and Osroes’ father), which makes Andragoras his half-brother. Andragoras also reveals that Osroes’ dies of sickness, and that it was actually Osroes who requests Andragoras to kill Hirmiz before he passed away. After that, he and Eleanor (princess of Maryam; they’ve known each other since they were teenagers) run off. At the opening of the second arc 4 years later, Eleanor has passed away, and Hirmiz uses the power of Turk’s king to created the Masked Army in an attempt to make a comeback. It didn’t work out. Then he meets a Parsian girl named Fitna, who promises to help him take over the Misr kingdom if he’d make her queen afterwards. It’s working so far.
