So this is the deck I got into masters with. Its mostly a Justice deck with a little Fire to enable FiLP, Rampage, and Mightweaver. Rampage allows the deck to blow through Chump blockers. FiLP is FiLP (though weaker now). Mightweaver allows the deck to end some games abruptly.
The deck generally is trying to end games fast but also can stall out and try and win in a big burst if your early draws are bad. I'm not sure if this is a midrange or aggro deck as it feels like its kinda on the boarderline between those two deck types. That is, it seems a little slow for an aggro deck but too fast for a midrange deck. Ideally the deck leads with a chainwhip Bludgeoner or Kodash evangel on turn 2 and then plays a kira on turn 3 with bubble shield in hand to protect it. From there you can start doing some explosive damage on turn 4 and 5.
Note 1 Combo: If you have Keira Ascending or Hooru Envoy in play, you can play Justice Etchings -> Fearless Crescendo -> Wind Conjuring to Draw 3 cards and have a ready flying attacker for 5 mana.
Note 2: I cut double fire influence cost cards like Ijin because the influence was too taxing on the deck to collect and it often resulted in not having enough Justice influence for trickshot Ruffian or Keira to have significant impact on the game. I cut Ironthorn Lawman from the deck as it felt too slow for the decks aggressive nature.
Bubble Shield
x4
1
Finest Hour
x4
1
Justice Etchings
x4
1
Silverblade Intrusion
x4
1
Trickshot Ruffian
x4
2
Chainwhip Bludgeoner
x4
2
Friends in Low Places
x4
2
Kira Ascending
x4
2
Kira, the Prodigy
x4
2
Kodosh Evangel
x4
2
Rampage
x4
3
Hooru Envoy
x2
3
Mightweaver
x4
Justice Sigil
x13
Justice Symbol
x4
Rakano Cylix
x4
Seat of Glory
x4
View Deck on Shiftstoned
Besides that a lot of the deck is knowing matchups. If you are playing against a shadow opponent you'll really be working to bait out unit destruction and protect your keiras with bubble shields. In contrast against the mono time builds you can generally get bold and just throw out a Kira on turn two because they more often than not don't have a killer unit to get rid of it in my experience. That said you want to be wary of Desert Alchemists against time decks and hold attacks until they can't play it, or you have silverblade intrusion to protect against deadly. Alternatively if you have rampage in hand, and you can do enough damage you can just sacrifice the kira to do massive damage to your opponent. I wouldn't do this play unless you have lethal or are getting 9ish damage in and have a follow up in hand though. While the deck is very aggressive by design, it is very limited on units and you don't want to throw them away like you might in a mono fire deck unless you see how the sacrifice is positioning you to win (or you got one of the hands that just drew 4 units which happens sometimes but isn't the normal in my experience). The decks strategy is very straightforward as you said, but there are a lot of contexts that make any individual piece of advice not hold for all situations. Those are some of my immediate tips. hope that helps.