Hola! Just wanted to make a thread about one of my favorite support champions Leona. I've done a little bit of research about her and just wanted to share some of my findings.
1.) Sunlight (Leona's passive): Leona's passive places a mark on all enemy champions that are hit by her abilities. This mark is consumed by allied champions when they deal damage to the marked target. When the mark is consumed sunlight deals additional damage based on leona's level. So first thing I found out about this ability is that the damage done by sunlight does not count as leona's damage but rather as damage done by the allied champion who procs the mark. This is important because it keeps leona from stealing kills while still allowing her to be a bursty support. Second, sunlight's damage is affected by magic penetration, but not leona's MP. Your allied champion's MP is taken into account because it is their damage. This could make leona a potentially interesting support to use if you ever felt like putting your ADC mid and putting an AP caster bot. (Ryze/Leona would be an OP lane, TONS of CC plus ryze fires a million spells a second making it easier to proc sunlight). Last thing I wanted to say about sunlight (I think most people know this but still important to say) is that you always want to try to time your abilities in between your allies autoattacks/spells because sunlight procs dont stack on the same target(however you can have multiple targets with the sunlight debuff on them at the same time). So zenith blade, start your Eclipse for the MR/AR and so it procs later when you want it to, let your adc AA, Shield of Daybreak, AA, ideally eclipse pops, adc AA. If you combo this correctly you are adding 105 damage at level 3! Thats quite a bit of damage on top of the damage from her abilities plus your ADC's burst. Also important to look at how sunlight's damage scales; 20 / 35 / 50 / 65 / 80 / 95 / 110 / 125 / 140. So at level 3 it jumps up to 35 damage and you should have all 3 of your abilities. If possible, ALWAYS engage at level 3. Your damage will be very high. Leona is strongest in the lane at levels 3, 5, 6, 7, and 9 because her passive gains extra damage at 3, 5, and 7 and because at 6 she gains an extra aoe stun/an extra ability to proc sunlight on.
Other side notes about sunlight: does not affect buildings, will not apply if it is blocked by black shield or banshee's veil or spellshield (the ability must do damage to apply the debuff), and sunlight does one less damage to all champions that are wearing sunglasses in their portrait. Vayne, surfer singed, all the commando skins, etc...
What to do at level 1 on Leona: Leona is not very strong at level one because it is difficult to get in range for her stun (if you take stun first) and if you take zenith blade first she has little that she can do with just that ability. So what i suggest is that you sit in your bottom bush with your stun. Place a ward in their bottom lane bush. Wait for their support to come up and ward your bush. When they do autoattack the ward once, then use your stun on it, then autoattack the ward again. Leona is one of the only champions that can do this (shyvana, maybe others) because shield of daybreak resets her autoattack timer. So you essentially can autoattack 3 times within 1 second. Keeping the enemy from having vision in your lane bush is HUGE for leona. It allows you to either completely zone them or set up easy kills because they don't see you coming. Always use this trick because leona excels at snowballing her lane and this can be just the advantage you need to get first blood.
Sidenote about Shield of Daybreak: Can be used to damage towers however it does not apply sunlight.
Zenith blade: One interesting mechanic on zenith blade is that it does not jump leona to mirror images. Mirror images include: shaco's hallucinate, wukong's decoy and leblanc's mirror image. Maybe this isn't the most important tip in the world but it may be able to net you a kill someday, IDK. Zenith blade provides an extremely short stun on the target. Basically the time it takes leona to get from where she is to her target enemy champion (so a little less then 0.5 seconds). If leona is CC'd or knockbacked during the casttime she will STILL jump to her target! If the target flashes or uses a blink mechanic she will STILL jump to her target's new location! If the target has blackshield, banshee's veil or spell shield on she will pop the shield but she will STILL jump to the target! In the case of banshee's veil and spell shield the target will still be immobilized for a short period of time but sunlight will not be applied. With black shield the immobilize will only apply if the shield exhausted from zenith blade's damage.
Side notes: Zenith blade can hit stealth champions and immobilize for a short period of time but it DOES NOT break stealth. (Tip: Cast solar flare on top of yourself if you hit a stealth target with zenith blade. Solar flare will stun and break the stealth). Zenith blade can be cast over walls and leona will jump the wall. If zenith blade hits multiple targets it will jump Leona to the last target hit. This makes it ideal for singling out squishy ADCs and APCs sitting in the back behind their tanks and bruisers.
Solar Flare: There aren't too many tips or tricks with this ability just know that it is an AWESOME ability. Don't forget that the stun does not proc immediately. You have to time this ability. Also, solar flare provides vision. Only time this would be important would be if you knew the enemy team was doing baron/dragon but you didnt have vision. You would have to cast solar flare, figure out where their squishies are (hopefully stunned squishies) and zenith blade to them.
Anyway, I hope you learned something about Leona today that you didn't already know. She is an extremely rewarding champion to play and a great alternative for people who don't normally like to play support. I encourage you to play her and experiment with her! Like i said it could be cool to try her with an AP caster bottom like ryze or maybe fiddlesticks. Someone with CC and lots of spells to proc her sunlight. In a traditional ADC lane try playing her with someone that has high early burst and a strong ult. Draven, trist, graves (my personal favorite), ezreal, ashe (for the CC), MF. Thanks guys! Enjoy your day!
Forgot to mention Summoner Spells! More often then not I take exhaust and flash however seeing Leona's take ignite over exhaust is becoming increasing popular. The advantage her is that you further enhance your early lane dominance with that extra damage. In my opinion ignite is viable but only against certain opponents. I would take ignite against; trist, corki, ezreal (they have solid escapes that make exhaust less useful as an aggressive spell. I would also take it against soraka to reduce heals (maybe sona too?). I don't know i still am experimenting with this. Any thoughts or opinions on ignite vs exhaust?