Twin Bites flat cooldown reduction is not effective against structures.
The only exception to Dragon FormTwin Bite applying on-hit effects to all affected targets is Titanic Hydra and Ravenous Hydra's passive effect Cleave, as it has an internal cooldown of 0.05 seconds when triggered on different targets. This is a special case to prevent abuse.
RANGE:162.5 / 350 / 365 / 380
Active:Shyvana surrounds herself in flame for 3 seconds, gaining bonusmovement speed that decays each second. Shyvana's basic attacks extend the duration of the effect by 1 second (on-hit), up to a maximum duration of 7 seconds.
Initial Movement Speed: 30 / 35 / 40 / 45 / 50%
Decay: 4.5 / 5.25 / 6 / 6.75 / 7.5%
While active, Shyvana deals magic damage every second and 25% of that damage on every hit to enemies surrounding her. Monsters take 20% increased damage.
Dragon Form:Flame Breath explodes upon hitting a champion or reaching the target location, dealing 100 - 200 (based on level)(+ 30% AP)bonus magic damage to them and surrounding enemies within a range and scorching the earth for 4 seconds. Enemies on scorched earth take 60 - 120 (based on level)(+ 20% AP) magic damage per second, and are persistently marked for Flame Breath's bonus on-hit damage.
Shyvana's basic attacks against marked enemies deal 2.5% of their maximum health as bonus magic damage, capped at 100 against monsters.
Dragon's Descent has an effective duration of 20 seconds when not attacking. If attacking continuously with a 2.5 attack speed, it has an indefinite effective duration. With Sated Devourer only attack speed of 1.67 is needed.
Dragon's Descent has an effective cooldown of 150 / 75 / 50 seconds when not attacking. When permanently attacking at 2.5 attack speed, it has an effective cooldown of about 17.65 / 15.8 / 14.3 seconds. Combined with Sated Devourer, the effective cooldown is reduced to 12.24 / 11.32 / 10.5 seconds.