There is no reliable way to put Dragonic Overlord in the soul before or after having placed this Unit as a Vanguard. Therefore, it is advisable to use 4 copies of Dragonic Overlord, and aim to Ride him and then Cross Ride this Unit on top. The only alternate way to place Overlord in the Soul within the Kagero clan would be Flame Edge Dragon or Vortex Dragon, but the former is too random and inconsistent, and the latter requires splitting the focus of your deck, which is not advisable, and at any rate usually takes up too much time and resources. If you cannot Cross Ride, you should simply try and win with either Overlord or The End at 11000 base Power.
This card isn't too heavy on Counter Blasting, and at any rate, your opponent will most likely try to dodge its skill by guarding it. So, using other units that can Counter Blast, specifically Berserk Dragon that can destroy important Units such as Special Intercepts, and Demonic Dragon Mage, Kimnara that can weaken your opponent's formation, either forcing them to devote more cards to the field or rendering them unable to effectively attack The End, as well as fill your soul for Aermo's effect, might be a good strategy.
If you aim to use this card specifically for its Persona Blast, rather than its defensive ability and overall Power, it is advisable to use units such as Doom Bringer Griffin, that can search The End out easily, and a multitude of draw triggers that can help you support its cost, or find The End themselves. You can also theoretically use Prowling Dragon, Striken and skip the Cross Ride, attacking with a +5000 Power, +1 Critical The End as early as your third turn. If you boost with Flame of Promise, Aermo, this can result in 26000 total Power, which will be very hard for your opponent to block without a Perfect Guard. If you have the damage and another copy of The End at the time, you can even finish the match in one turn.
Use Lizard Soldier, Conroe to search out Doom Bringer Griffin, Grapeshot Wyvern, or Flame of Promise, Aermo to support the above strategy.
It is debatable what triggers you should use alongside The End. Stand triggers generally only shine if you pull one on the turn you activate this card's Persona Blast, so they are rather situational. Comparatively, Critical triggers during that turn are just as fearsome, and can help push for damage under most circumstances. On the other hand, Draw triggers can help you defend better (since most of the time, 5000 Shield will be enough to protect The End if Dragonic Overlord is in the Soul, and draw triggers can prevent you from needing to either overguard or sacrifice more useful Units), and can also help you get the necessary copies of The End in the hand.
Most of the time, your opponent will guard against The End out of fear of its Persona Blast, and let your Rear Guards hit. Take advantage of this by using Bellicosity Dragon, which can recover damage you use for Conroe or other Units.
The fact that your opponent might devote a lot of resources to guarding The End is something you can use to your advantage. If you keep your resources reasonably hidden, so that your opponent is almost certain you have a spare The End in the hand, he will likely keep blocking The End's attacks. Then, you can use your rear-guards to pick at his Rear Guards, reducing his card count and biding your time until you actually get The End in your hand and are able to finish the match in one stroke. Be careful about your soul count, if using Flame of Promise, Aermo.
Keep hitting the opponent's Vanguard is good for reducing their handsize, but if it's you that is running low, and you have a copy of The End in your hand, take down the useless or most precious Rear-guard for them. Eg.: 12k attacker rear-guard. if you want to decrease your opponent's hand and there's a chance that your enemies won't guard for them, allowing you to go for a Persona Blast, attacking once more, and this time go for their Vanguard.
Ride this over Dauntless Drive Dragon to increase the chances of its attack hitting. The break ride unit's effect to stand again can be used as a last resort if Dragonic Overlord the End doesn't hit the first time, although you will lose 1 card.
While this card has a very powerful Persona Blast and is difficult to hit with 13000 Power, using it at full potential requires at least 3 Grade 3s (1 Dragonic Overlord and 2 The Ends or 1 Dauntless Drive Dragon and 2 The Ends). Keep a consistent way to mantain hand advantage as you lose 2 cards which could be used as rearguards and needing that many Grade 3s can affect your ability to guard before using the Persona Blast itself.
You may combo this card with Dragonic Overlord (Break Ride) to reduce an opponent's Intercept.