With a request from @OmegaKrypton, who is my best friend (one of), I'm doing part 3 earlier.

The wall suddenly opened by itself and Cyrus saw a dark room at the end. Cyrus walked carefully along the pathway and arrived at a dark room. Inside the dark room, there were many electrical components. Cyrus was confused since he discovered these ruins in a primitive forest. He searched through the goods and found a hidden box. There was a cryptograph only with numbers next to it. Next to it were a bunch of letters...

OKrZnPtRbAs

Cyrus knew that it was a riddle again. Can you solve it for him?

Hints:

+-×÷

There is a hidden easter egg! Can you find it?

• Thanks @Hugh for helping me correct the grammar mistakes! Commented Feb 19, 2019 at 13:30
• Can anyone find the Easter Egg? Commented Feb 19, 2019 at 13:31
• is the hidden Easter egg the EA of Easter which in this case would refer to Electron affinity? Commented Feb 19, 2019 at 17:13
• Is the Easter Egg relevant to the puzzle? If not, I would say that it is rot13((Bzrtn)Xelcgba orvat cneg bs gur chmmyr) Commented Feb 19, 2019 at 19:10
• @mrdeadsven Yes! Commented Feb 20, 2019 at 4:54

Partial:

OKrZnPtRbAs

are symbols of chemical elements: Oxygen Krypton Zinc Platinum Rubidium Arsenic (atomic numbers 8, 36, 30, 78, 37, 33)

Then

Add the sum of the atomic numbers to get 222.

And is it the end?

• Z usually refers to the number of protons in the nucleus from a periodic element Commented Feb 19, 2019 at 12:05
• Sorry it should be Zn instead of Z Commented Feb 19, 2019 at 13:28
• Sorry for any inconvenience caused Commented Feb 19, 2019 at 13:30
• shouldn't the last one be 'Arsenic' atomic number 33 as Astatine is At? Commented Feb 19, 2019 at 16:15
• @KSharing is this the end? thanks! Commented Feb 20, 2019 at 6:19

Partial: I might be going into the complete wrong direction here but:

he said there were electrical components so my best guess is it has to do with the electrons of the elements (because electrical components affects electrons)

so we get

the amount of electrons is O=8 Kr=80 Zn=35 Pt=78 Rb=48 and As=33.

And lastly

If we look into the periodic table we can see that for O, Pt and As they are the same as the amount of electrons. So maybe this is something to the answer Oxygen->Platinum->Arsenic to open it? Or maybe the number sequence 87833?

• You are on the right track :) Commented Feb 20, 2019 at 4:55