Moves
Hone Claws increases Zekrom's already great damage output, letting it OHKO bulky walls such as Lugia, offensive Necrozma-DM, and Magearna after a boost, as well as making Bolt Strike a perfectly accurate move.
Bolt Strike is Zekrom's strongest STAB move and inflicts massive damage on neutral foes, notably achieving a 2HKO on fast support Arceus forms formes. It also has a decent chance to paralyze a foe.
STAB Outrage, although quite dangerous to be locked into, allows Zekrom to use a powerful Devastating Drake with Dragonium Z. After a boost from Hone Claws, it features an incredible showcase of damage output by OHKOing most Primal Groudon variants, Arceus-Ground, and Zygarde-C.
Substitute allows Zekrom to ease prediction and take advantage of its ability to force switches. It also gives Zekrom a better matchup against defensive teams by punishing foes that try to play around Devastating Drake or use a status move. Another notable benefit of Substitute is that Zekrom can use defensive Necrozma-DM and Ferrothorn as setup fodder.
Set Details
The given EV spread allows Zekrom to avoid the OHKO from Arceus-Ground and Arceus-Fairy's Judgment, the OHKO from Mega Salamence's Earthquake after Stealth Rock, and the 2HKO from support Arceus formes' Ice Beam while letting Zekrom outspeed Adamant Necrozma-DM.
Maximum investment on Attack with an Adamant nature maximizes Zekrom's damage output, letting it 2HKO certain Arceus formes with Bolt Strike.
Dragonium Z allows Zekrom to use Devastating Drake so it can use a Dragon-type STAB move without locking itself into Outrage.
Teravolt is Zekrom's only legal ability and notably allows it to hit Lugia through Multiscale and KO the occasional Skarmory through Sturdy. Bear in mind that this ability does not ignore Lunala's Shadow Shield.
Usage Tips
Due to its horrendous matchup against faster threats, Zekrom is best used as a wallbreaker that paves the way for its teammates to sweep by disposing of major threats such as Primal Groudon, Arceus-Ground, Ho-Oh, and Zygarde-C.
Zekrom possesses good natural bulk and offensively checks a number of threats by its typing, but it should generally avoid switching into attacks due to its exploitable weakness to common coverage moves such as Ice Beam from support Arceus formes and status move severely crippling it. Pivoting via U-turn and Volt Switch and double switching are the most ideal ways for Zekrom to switch in.
Despite the fact that Zekrom has a way to lure and remove Ground-types, such foes usually limit Zekrom's offensive capabilities, as they discourage the use of Bolt Strike and force Zekrom to make flawless predictions with setting Hone Claws on their switch. This means one's prediction is going to determine Zekrom's performance against practically any team due to the abundance of Primal Groudon, and this becomes more of a serious matter against team with Arceus-Ground.
When given an opportunity to switch in, it is important to decide whether to attack or set up Hone Claws; due to the prevalence of Ground- and Fairy-types on most teams, Zekrom will most likely struggle to inflict much damage without having them weakened or eliminated.
Early-game, Zekrom can pressure the opposing team with strong Bolt Strikes and potentially spread paralysis so it will have the upper hand against paralyzed foes later.
If Ground-types such as Primal Groudon and Arceus-Ground are likely going to switch in, setting up Hone Claws is a promising idea, as a healthy Zekrom can survive a hit from the latter and OHKO back with boosted Devastating Drake. In order for this to be successful, avoid taking any form of damage so Zekrom can successfully lure Arceus-Ground, survive a Judgment, and score a KO.
If Zekrom is boosted, and if there are Fairy-types present on the opposing team, use Substitute to ease predictions with your Z-Move, as they can make Zekrom's opportunity to wallbreak go to waste simply by switching in.
In an event where Zekrom has no opportunity to set up Hone Claws, unboosted Devastating Drake can still be used to significantly weaken threats like Primal Groudon and most neutral targets so that Zekrom's teammates, such as Primal Kyogre and Xerneas, can have easier time dealing with them.
Zekrom can take more offensive approaches to dish out damage against slower and defensive teams. It can be sent out early to threaten certain bulky foes such as Lugia, Ho-Oh, and Skarmory and set Substitute to avoid status while easing predictions with Devastating Drake.
Team Options
Zekrom's objective is to rid the opposing team of threatening foes such as Primal Groudon and Arceus-Ground so its teammates can function more effectively. Teammates that appreciate the disposal of such foes can fit alongside Zekrom.
Offensive powerhouses such as Primal Kyogre, Marshadow, and Ho-Oh vastly appreciate Zekrom disposing of Primal Groudon with a powerful Devastating Drake. Setup sweepers that appreciate the removal of Primal Groudon, such as Xerneas, Arceus, and Necrozma-DM, appreciate this as well. In return, Zekrom checks Ho-Oh and Lugia, which can otherwise be nuisances to deal with for certain mentioned teammates.
Entry hazards allow Zekrom to score the OHKO on defensive Primal Groudon with Devastating Drake and 2HKO on support Arceus formes with Bolt Strike. Primal Groudon and Necrozma-DM can set such entry hazards while checking Fairy-types and hindering support Arceus formes with Toxic. On more offensive teams, Deoxys-S, Excadrill, and Cloyster can set hazards for Zekrom.
Despite the fact that Zekrom can KO Primal Groudon and Arceus-Ground with a boosted Z-Move, it is advised to acquire a check for them, as luring and KOing them require predictions. Arceus-Water is a solid check to both of the threats and appreciates Zekrom taking advantage of defensive Necrozma-DM and Toxapex. Giratina-O, although it stacks weaknesses with Zekrom, is one of the more offensive checks to Primal Groudon and can provide better setup opportunities for Zekrom by weakening a foe with Will-O-Wisp.
Arceus-Ground serves as a solid offensive check to Primal Groudon, and Calm Mind variants in particular appreciate Zekrom's ability to deal with most of its checks like Ho-Oh, Primal Kyogre, and Celesteela.
Mega Salamence is a good teammate that provides an immunity to Ground, and it benefits from Zekrom's ability to threaten Arceus-Water and Toxapex, immensely pressure Arceus-Fairy, and potentially lure and eliminate Arceus-Ground.
Ho-Oh is a solid check to Fairy-types, support Arceus-Ground, and Primal Groudon without a Rock-type move. It also appreciates Zekrom's ability to offensively check Water-types.
Steel-types generally tend to pair well with Zekrom, as they can switch into Toxic and Ice-type moves while checking Fairy-types. Zekrom threatens Ho-Oh and can get rid of Primal Groudon, both of which are massive threats to Steel-types. Mega Scizor and Magearna can bring in Zekrom safely with U-turn and Volt Switch, Ferrothorn can set Spikes and wear down Arceus formes with Leech Seed and Toxic, and Celesteela can aid Zekrom in the same way and also provides Ground immunity. Offensive Necrozma-DM appreciates Zekrom threatening Yveltal and Ho-Oh while eliminating one of its greatest checks, Primal Groudon.
Mega Gengar can trap and remove Fairy-types, which are one of the biggest problems for Zekrom to deal with, so Zekrom can use Devastating Drake without much concern. In return, Zekrom has the ability to remove Primal Groudon, Ho-Oh, and Yveltal, all of which Mega Gengar struggles to beat.
Yveltal pressures most physical walls in the tier with strong attacks and can potentially provide a setup opportunity for Zekrom by crippling a passive foe with Taunt. Variants with U-turn can also bring in Zekrom safely.
Sticky Web is an interesting option that lets Zekrom overcome its rather mediocre Speed tier and threaten faster foes that it otherwise struggles against. Smeargle can set Sticky Web so Zekrom will outspeed most grounded foes, and Zekrom pressures most Defog users with its STAB moves and offensively checks Yveltal and Mega Salamence, both of which are serious problems for Sticky Web teams to deal with.