Strictly speaking, this is the only set Ninjask should be running competitively. The concept behind this set is very simple on paper: utilize Protect and Substitute to safely acquire Speed boosts, then proceed to pass them off to the appropriate sweeper. Substitute serves a secondary purpose on this set as a buffer for both Ninjask and the recipient, protecting them from becoming compromised by status or Dragon Tail and Circle Throw, while also reducing the necessity for either to take strong hits. With that in mind, it is very rare that Ninjask has either the opportunity or the necessity to use anything other than its first three moves. However, the fourth move does offer Ninjask a degree of additional utility, and does somewhat affect how it plays. In terms of sheer potency, Swords Dance is far and away the most dangerous option—while it is very rare that Ninjask finds the opportunity to both set up a Swords Dance and bring in the proper recipient safely, the results can be devastating. On the other hand, while not nearly as threatening, Toxic is a useful and self-sufficient option for Ninjask. The cumulative chip damage Toxic provides not only synergizes nicely with the cycles of Substitute and Protect Ninjask commonly undergoes but can, at times, even force the opponent to switch out to preserve the poisoned Pokemon, which can open up a free turn for Ninjask to effectively pass off its boosts to a teammate safely.
As straightforward as this process appears in theory, it requires substantially more prediction on the part of the Ninjask user in practice. While you can very well get up to +6 Speed by constantly using Protect and Substitute in succession, this not only wastes much more of Ninjask's HP than probably necessary but is also incredibly predictable and very exploitable by a knowledgeable opponent. A very simple and effective method of keeping opponents on their toes is to avoid setting up to +6 except for in the most dire situations—it might sound odd to not acquire as many boosts as possible, but once Ninjask acquires all the Speed boosts it possibly can, it's left with nothing much else to do but attempt to Baton Pass, which makes it all the easier for the opponent to nail the switch-in with a powerful attack. It is very rare that a Pokemon needs all of those Speed boosts to outpace the entirety of the opponent's team; simply boosting to the necessary level both saves PP and HP for Ninjask and makes predicting the Baton Pass all the more difficult.
Moreover, it is important to note that having a Substitute up when Ninjask attempts the Baton Pass should hold priority over almost everything else, even if this means sacrificing an extra Speed boost or two in doing so. Having a Substitute active not only completely protects the Baton Pass recipient from everything barring multi-hit attacks and certain non-attacking moves that it might have otherwise struggled to switch into, but also gives it assurance against priority users and particularly fast Choice Scarf users afterwards, which effectively mitigates any Speed boosts the sweeper might have "lost" by forgoing the extra turns of boosting with Ninjask. While it isn't necessarily easy to maintain a Substitute, by mixing up the use of Protect and Substitute, rather than simply alternating between the two, Ninjask can do its recipient a much bigger favor than any extra one or two Speed boosts ever will. However, it should be noted that without users of phazing or multi-hit moves already disposed of, these boosts are practically forfeit, as such Pokemon can quickly neutralize Ninjask or its recipient.
The given EV spread maximizes Ninjask's physical bulk in order for it to better take on priority attacks, with a Timid nature and 16 Speed EVs ensuring that it outpaces Aerodactyl without a boost, as well as Unburden Hitmonlee at +1. In terms of item choice, Leftovers is often preferable, as the passive recovery not only allows Ninjask to produce more consecutive Substitutes, but also helps put it just outside the KO range of priority attacks, such as Entei's Extreme Speed, by using Protect when necessary. However, due to the fact that Ninjask very often only gets a single chance to set up, other items that can open up more opportunities aren't outside the realm of possibility. Lum Berry is one such example, as this allows Ninjask to more comfortably switch into defensively-inclined Pokemon, such as Clefable, Poliwrath, and Uxie, and proceed to accumulate boosts. Mental Herb gives Ninjask a chance to neutralize a single Taunt, allowing it to pick up a few more boosts against Pokemon such as Qwilfish, though the limited pool of effective Taunt users makes this a less consistently useful option than either Leftovers or Lum Berry.
As elaborated upon earlier, Ninjask has very little use for much beyond its first three moves, so its final moveslot can be effectively tinkered with to achieve different results depending on individual necessities. A STAB move, such as X-Scissor or Aerial Ace, while not realistically making Ninjask any less vulnerable to Taunt, does offer Ninjask a method of dealing damage, which can at times prove useful for picking off weakened Grass- and Fighting-types it can occasionally switch into. Roost is also technically a possibility, as it could potentially increase Ninjask's lifespan to the point where it could attempt to pass boosts a second time, but typically teams utilizing Ninjask are too fast-paced and offensive to want to extend the match this long.
Because Ninjask is almost entirely support-based in terms of its role, it is more important to focus on what benefits the most from its abilities first and foremost, rather than supporting it, when picking partners. The most appropriate partners for this role are those with high immediate power and the natural bulk and/or resistances necessary to comfortably stomach a priority move or even a weaker attack when switching in, with Ninjask's Speed boosts putting them comfortably outside the range of most Speed-reliant revenge killers. Ideally, these Pokemon should possess good defensive synergy with Ninjask in addition to possibly resisting common coverage options, as this makes predicting the Baton Pass more difficult and thereby dangerous. There are many options for this, which include Aggron, Crawdaunt, Druddigon, Durant, and Emboar, and it would be in one's best interest to utilize multiple recipients in order to diversify the potential threats to best suit various different match-ups. Kabutops should be given special acknowledgment in this role, as it provides the option of Rapid Spin to give Ninjask a bigger window to set up mid-game. Lastly, and while it might seem excessive, dual screens support is a very realistic option for Swords Dance variants of Ninjask—passing a Swords Dance boost in addition to the standard Speed boosts can very often be game-ending if executed properly, and thus very much worth the investment in dual screens. Uxie is the ideal partner for this role, as it can quickly set up screens, provide Stealth Rock support, and get out of the way via Memento, efficiently setting the stage for Ninjask to set up safely.
