This card overcomes the main weakness of "Buster Blader", that it relies on the opponent using a specific kind of monster to power up. This card powers up if Dragons are also used on your side, making it extremely handy.
A card that combos extremely well with this is "Mirage Dragon". It doesn't completely lock down Traps, but it prevents your opponent from using Traps during the Battle Phase, which tend to be the most troublesome Traps, and boosts this card's ATK by 500 at the same time.
If there are two in your Deck, this combo can help a lot. "Fusion Recovery" and "Emblem of Dragon Destroyer" is needed. Play "Polymerization" and then "Fusion Recovery" in which "Dark Magician" and "Polymerization" are retrieved from the Graveyard. Then play "Emblem of Dragon Destroyer" to regain "Buster Blader" and re-Fuse.
The effect of "Dark Paladin" can be used to discard "Ojamagic", giving more cards to discard due to "Ojamagic".
If there is an empty field, an OTK can be attempted with this card. Attack directly with "Dark Paladin", then activate "De-Fusion" to Special Summon "Dark Magician" and "Buster Blader" from your Graveyard. Attack directly with both for exactly 8000 damage (2500 + 2600 + 2900 = 8000).
Activate "Raigeki" to clear your opponent's side of the field, then attack directly with "Dark Paladin", and continue with the above OTK strategy.
Use "King of the Swamp" to make "Dark Paladin" easier to Summon, since it can act as a Fusion substitute and a way to search out "Polymerization". Using "King of the Swamp" also allows on either "Dark Magician" or "Buster Blader", without having to include the other one in your Deck.
If a "Dark Paladin"-themed Deck is used, some good cards to use are:
"Elemental HERO Woodsman" to recycle one "Polymerization" each turn to use the effect of "Dark Paladin" or to Summon "Dark Paladin".
"The Eye of Timaeus" can instantly Summon this card without even needing anything other than "Dark Magician" in the Deck.
If there is "The Eye of Timaeus" and either "Elemental HERO Prisma", or a card that can search out "Prisma", in your hand, this card can be Summoned almost immediately: use the effect of "Prisma" to send "Dark Magician" to your Graveyard and change its name to "Dark Magician", then use "The Eye of Timaeus" on it to Fusion Summon "Dark Paladin". (This combo also works with "Amulet Dragon" and "Dark Flare Knight" as well.)
This card can work well with "Red-Eyes Black Dragon Sword" as this card effect is similar to "Dark Paladin" increasing its ATK by twice the amount.
By having "Fusion Sage", "Emblem of Dragon Destroyer", "Future Fusion" and on the field "Skilled Dark Magician", use first "Fusion Sage" to bring "Polymerization", then "Emblem" to add "Buster Blader" to your hand and finish with "Future Fusion" to Summon "Five-Headed Dragon". Then use the effect of "Skilled Dark Magician" to bring "Dark Magician" on your field and fuse it to bring "Dark Paladin" with an attack of 5400. And later there would be your "Five-Headed Dragon" with 5000 ATK, and also increase the ATK of "Dark Paladin" to 5900.