Went pretty deep in the hunt for Shiny Registeel!

Took 3025 Resets, which is still under the actual odds of 1/4096.

I used an Umbreon with Synchronize and Impish Nature to force the nature of the Shiny Registeel to also be Impish.

I used a Breloom to constantly 'Spore' and 'False Swipe' to maximize capture odds.

Took about 25 Luxury Balls when Registeel was 1HP and Asleep.

Best IVs in HP, Attack, and Speed.

Hunt History:
Shiny Palkia had taken me over 3000+ Resets
Shiny Dialga took 689 Resets
Shiny Giratina took 2915 Resets

Next Shiny Hunt:
Shiny Regirock [Ramanas Park]
Impish Nature - 3IV+
Luxury Ball