Hello! Today, I am here to talk about my Leona bruiser build that I've been working on and testing for quite some time now. When it comes to playing her as a bruiser, you'll need to remember to be patient with this character, and always have confidence. She does fairly well in the mid-late game, but in the end, there will always be better top lane characters that you'll have to fight against.

Pros: Can safely get farm fairly well, when people attempt to engage she can easily get out of it with her stun, can counter tower dives and punish them.
When it comes to Leona in 1v1s, depending on your farm, and kills, she usually won't be able to 1v1 many people in the early games because of the lack of damage. When it comes to team fights however, she does a surprisingly good amount of damage to single targets, while providing her team with the many stuns she has.
Cons: Can get pressured easily by top-lane bullies, if caught pushed too far up, can be ganked and punished easily, doesn't have good enough damage to properly 1v1 early game against her laner thus making her rely on her stuns to safely get out with full health.
The main problem with Leona bruiser is that her damage is so low in the early games, that she really struggles against lane bullies, and can't contest their damage or their poke. She is forced to play safe and farm under tower.

Resolve
(Grasp of the Undying): Grasp is helpful for if you ever get in attacking range, and want to get your stun off, then you can attack them, while applying the stun and on top of that you'll gain back some health.
(Bone Plating): Plating simply helps you against champs that want to poke or harass you in your lane.
(Second Wind): Once again, getting pressured in the 1v1 laning faze will make it hard for you to live, so having second wind will once again help against the enemy laner when they try to attack/hurt you.
(Overgrowth): Overgrowth is one of my personal favorite keystones. This just makes you slowly more and more tanky, thus helping you be a good bruiser while in the team fights.
(Demolish}: Having demolish on this build will help you secure and split more often when you notice yourself in a good position to take turrets. Since the turrets have a "turret plating", demolish will make it easier (In theory), to get turrets.
Precision
(Legend:Alacrity):This will help you gain more attack speed to help crank out that damage which will be important in the mid-late game.
(Coup de Grace): Coup de Grace just helps you deal more damage in the team fights after you land a stun on a target.

Starting Items: Getting doran's shield is going to be more useful then doran's blade because your objective when playing Leona top is to try and collect farm and survive the enemy pokes. Having shield just helps make you have that extra self-sustain that you need in order to live.
First Back: Since Leona has a hard time with killing/clearing waves, getting tiamat will help her out a bit in collecting more farm.
Early Buys: Getting phage and kindlegem help you out a bit more against your laner, and now it also allows you to push your wave up, and roam to a different lane. With the phage, you are now able to deal a bit more damage. Kindlegem helps with some tank, plus it builds into black cleaver, which you'll be building next.
Core Items: You'll need to build black cleaver first so you start to rack up more damage. Getting titanic hydra next will just help add onto the better wave clearing, and finally getting trinity force will help you all-around with everything.
Final Build: Getting maw will help you if the enemy has any strong AP champions that are doing a bit of damage to you. Sunfire cape will be really useful in team fights because when you go in for a stun, if all the enemies are near/close to you, this will rack up some damage on then while you are also dishing out your own damage.
Other Defensive Items: If you see that the enemies have more AD then AP, or vis versa, then you can always switch out some items in the build for more defensive items that can help you be more tanky against them. I would mainly switch to defensive items if you are ever getting bursted down quickly, or if you are ever behind a bit.
Other Offensive Items: If you are ever ahead, and the enemy champions don't hurt you too much, then don't be afraid to build any of these offensive items. These items can also be helpful if you aren't necessarily ahead or behind.