McCullum's team had come into the series ranked eighth in the world after a humiliating series loss in South Africa marked by a first innings dismissal for 45 runs in the opening Test.
Alastair Cook's England arrived having overhauled India 2-1 in a rare series win in the subcontinent and with few pundits regarding the New Zealand tour as much more than a warm-up for back-to-back Ashes series later in the year.
The tourists instead found a combative New Zealand side who held the upper hand for most of the drawn series and but for Matt Prior's defiant fifth-day century in the third and final Test at Eden Park, would surely have clinched it.
"It was never about redemption," McCullum said of his team's revival since their South Africa doldrums. "For us it's about standing up and doing justice in your role as a New Zealand cricketer.
"That's a strong message that gets filtered throughout this team. We are no means the finished product but we are starting to perform."
Among the biggest problems facing New Zealand in recent years has been a lack of stability at the top of the order, which has allowed opponents to tear into the middle order early in conTests.
The recalled Peter Fulton and introduction of Hamish Rutherford, however, may have solved that problem.
Rutherford scored a brilliant century on debut in Dunedin, while Fulton became only the fourth New Zealand batsman to score a ton in both innings of a Test with his Eden Park heroics.
With Kane Williamson maturing into a top-class batsman after years of promise, New Zealand showed an encouraging mix of resilience, patience and attacking flair in their top three.
"I think the top of the order for us, which has been such a huge problem for us for so long ... was a great story," said McCullum, whose return to the middle order also reaped dividends.
The swashbuckling captain scored 248 runs in four innings at an average of 82.67 in the series and was involved in partnerships with the middle and lower order that contributed a third of New Zealand's total runs.
"It's going quite nicely," McCullum said. "The shift down the order has given me a bit more freedom to be a bit more authentic in my style and my approach to the game as well.
"Those few years up the top I really enjoyed it. The makeup and balance of our side now, I'm just better suited down the order."
New Zealand's bowling stocks have also been boosted with Trent Boult growing in confidence.
Boult, Tim Southee, Neil Wagner, Doug Bracewell and the injured Mitchell McClenaghan, who could force his way into Test contention after an impressive limited overs performance, are all under 27 years old and will push each other for pace bowling spots in coming years.
"We have quite a few guys waiting in the wings and that's encouraging for us," McCullum said.
"If you look back on a couple months ago we were starting to search a little bit. Now we're starting to bed down a group of players that are capable of moving this team forward.
"We are trending in the right direction and that's nice."
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