you see him at spear pillar where you catch palkia and dialga or arceus
the east of hearthome
theres no such thing
mount coronet is in the sinnoh region. that's Pokemon diamond pearl and platinum.
Mt. Coronet (middle) peak
You buy a gameshark ad cheat through it.
same place as in Pokemon D/P, west from celestic, east from eterna, and south-east from snowpoint.
The first time you see Cyrus is at Lake Verity
In Pokemon Platinum, you don't battle Cyrus at Spear Pillar. Instead, you fight him in the Distortion World. After beating him, Cynthia heals your Pokemon and then you battle Giratina.
Cyrus is only in Pokemon Diamond Pearl and Platinum. Nobody knows what happened to him after he disappeared in DPPl.
cyrus gives it to you
in the galactic warehouse
After releasing the three Pokemon of the lakes, Cyrus goes to the top of Mt. Coronet